Gtilab.com refuses SSH connection, but only sometimes

I configured an SSH key in my profile.
When I git fetch in a repository about half of the times it succeeds and the other half the connection is refused with this message:

git@gitlab.com: Permission denied (publickey,keyboard-interactive).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

I’m using Git 2.28.0 and OpenSSH 8.4p1 (with ssh-agent) on Fedora 33.

Output of failing run of GIT_SSH_COMMAND="ssh -vvv" git fetch:

OpenSSH_8.4p1, OpenSSL 1.1.1h FIPS 22 Sep 2020
debug1: Reading configuration data /etc/ssh/ssh_config
debug3: /etc/ssh/ssh_config line 55: Including file /etc/ssh/ssh_config.d/50-redhat.conf depth 0
debug1: Reading configuration data /etc/ssh/ssh_config.d/50-redhat.conf
debug2: checking match for 'final all' host gitlab.com originally gitlab.com
debug3: /etc/ssh/ssh_config.d/50-redhat.conf line 3: not matched 'final'
debug2: match not found
debug3: /etc/ssh/ssh_config.d/50-redhat.conf line 5: Including file /etc/crypto-policies/back-ends/openssh.config depth 1 (parse only)
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
debug3: gss kex names ok: [gss-curve25519-sha256-,gss-nistp256-sha256-,gss-group14-sha256-,gss-group16-sha512-]
debug3: kex names ok: [curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512]
debug1: configuration requests final Match pass
debug1: re-parsing configuration
debug1: Reading configuration data /etc/ssh/ssh_config
debug3: /etc/ssh/ssh_config line 55: Including file /etc/ssh/ssh_config.d/50-redhat.conf depth 0
debug1: Reading configuration data /etc/ssh/ssh_config.d/50-redhat.conf
debug2: checking match for 'final all' host gitlab.com originally gitlab.com
debug3: /etc/ssh/ssh_config.d/50-redhat.conf line 3: matched 'final'
debug2: match found
debug3: /etc/ssh/ssh_config.d/50-redhat.conf line 5: Including file /etc/crypto-policies/back-ends/openssh.config depth 1
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
debug3: gss kex names ok: [gss-curve25519-sha256-,gss-nistp256-sha256-,gss-group14-sha256-,gss-group16-sha512-]
debug3: kex names ok: [curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512]
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts' -> '/home/username/.ssh/known_hosts'
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts2' -> '/home/username/.ssh/known_hosts2'
debug2: resolving "gitlab.com" port 22
debug2: ssh_connect_direct
debug1: Connecting to gitlab.com [172.65.251.78] port 22.
debug1: Connection established.
debug1: identity file /home/username/.ssh/id_rsa type 0
debug1: identity file /home/username/.ssh/id_rsa-cert type -1
debug1: identity file /home/username/.ssh/id_dsa type -1
debug1: identity file /home/username/.ssh/id_dsa-cert type -1
debug1: identity file /home/username/.ssh/id_ecdsa type -1
debug1: identity file /home/username/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/username/.ssh/id_ecdsa_sk type -1
debug1: identity file /home/username/.ssh/id_ecdsa_sk-cert type -1
debug1: identity file /home/username/.ssh/id_ed25519 type -1
debug1: identity file /home/username/.ssh/id_ed25519-cert type -1
debug1: identity file /home/username/.ssh/id_ed25519_sk type -1
debug1: identity file /home/username/.ssh/id_ed25519_sk-cert type -1
debug1: identity file /home/username/.ssh/id_xmss type -1
debug1: identity file /home/username/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.4
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.4p1 Debian-10+deb9u7
debug1: match: OpenSSH_7.4p1 Debian-10+deb9u7 pat OpenSSH_7.0*,OpenSSH_7.1*,OpenSSH_7.2*,OpenSSH_7.3*,OpenSSH_7.4*,OpenSSH_7.5*,OpenSSH_7.6*,OpenSSH_7.7* compat 0x04000002
debug2: fd 4 setting O_NONBLOCK
debug1: Authenticating to gitlab.com:22 as 'git'
debug3: hostkeys_foreach: reading file "/home/username/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/username/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from gitlab.com
debug3: order_hostkeyalgs: have matching best-preference key type ecdsa-sha2-nistp256-cert-v01@openssh.com, using HostkeyAlgorithms verbatim
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,ext-info-c
debug2: host key algorithms: ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,sk-ssh-ed25519-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ecdsa-sha2-nistp256@openssh.com,ssh-ed25519,sk-ssh-ed25519@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: aes256-gcm@openssh.com,chacha20-poly1305@openssh.com,aes256-ctr,aes128-gcm@openssh.com,aes128-ctr
debug2: ciphers stoc: aes256-gcm@openssh.com,chacha20-poly1305@openssh.com,aes256-ctr,aes128-gcm@openssh.com,aes128-ctr
debug2: MACs ctos: hmac-sha2-256-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha2-256,hmac-sha1,umac-128@openssh.com,hmac-sha2-512
debug2: MACs stoc: hmac-sha2-256-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha2-256,hmac-sha1,umac-128@openssh.com,hmac-sha2-512
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@openssh.com,zlib
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com
debug2: compression stoc: none,zlib@openssh.com
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: aes256-gcm@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: aes256-gcm@openssh.com MAC: <implicit> compression: none
debug1: kex: curve25519-sha256 need=32 dh_need=32
debug1: kex: curve25519-sha256 need=32 dh_need=32
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:HbW3g8zUjNSksFbqTiUWPWg2Bq1x8xdGUrliXFzSnUw
debug3: hostkeys_foreach: reading file "/home/username/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/username/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from gitlab.com
debug3: hostkeys_foreach: reading file "/home/username/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/username/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from 172.65.251.78
debug1: Host 'gitlab.com' is known and matches the ECDSA host key.
debug1: Found key in /home/username/.ssh/known_hosts:1
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey out after 4294967296 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey in after 4294967296 blocks
debug1: Will attempt key: /home/username/.ssh/id_rsa RSA SHA256:xxxxx agent
debug1: Will attempt key: /home/username/.ssh/id_dsa 
debug1: Will attempt key: /home/username/.ssh/id_ecdsa 
debug1: Will attempt key: /home/username/.ssh/id_ecdsa_sk 
debug1: Will attempt key: /home/username/.ssh/id_ed25519 
debug1: Will attempt key: /home/username/.ssh/id_ed25519_sk 
debug1: Will attempt key: /home/username/.ssh/id_xmss 
debug2: pubkey_prepare: done
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,ssh-rsa,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,keyboard-interactive
debug3: start over, passed a different list publickey,keyboard-interactive
debug3: preferred gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /home/username/.ssh/id_rsa RSA SHA256:xxxxx agent
debug1: send_pubkey_test: no mutual signature algorithm
debug1: Trying private key: /home/username/.ssh/id_dsa
debug3: no such identity: /home/username/.ssh/id_dsa: No such file or directory
debug1: Trying private key: /home/username/.ssh/id_ecdsa
debug3: no such identity: /home/username/.ssh/id_ecdsa: No such file or directory
debug1: Trying private key: /home/username/.ssh/id_ecdsa_sk
debug3: no such identity: /home/username/.ssh/id_ecdsa_sk: No such file or directory
debug1: Trying private key: /home/username/.ssh/id_ed25519
debug3: no such identity: /home/username/.ssh/id_ed25519: No such file or directory
debug1: Trying private key: /home/username/.ssh/id_ed25519_sk
debug3: no such identity: /home/username/.ssh/id_ed25519_sk: No such file or directory
debug1: Trying private key: /home/username/.ssh/id_xmss
debug3: no such identity: /home/username/.ssh/id_xmss: No such file or directory
debug2: we did not send a packet, disable method
debug3: authmethod_lookup keyboard-interactive
debug3: remaining preferred: password
debug3: authmethod_is_enabled keyboard-interactive
debug1: Next authentication method: keyboard-interactive
debug2: userauth_kbdint
debug3: send packet: type 50
debug2: we sent a keyboard-interactive packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,keyboard-interactive
debug3: userauth_kbdint: disable: no info_req_seen
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
git@gitlab.com: Permission denied (publickey,keyboard-interactive).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

Output of succeeding run of GIT_SSH_COMMAND="ssh -vvv" git fetch:

OpenSSH_8.4p1, OpenSSL 1.1.1h FIPS 22 Sep 2020
debug1: Reading configuration data /etc/ssh/ssh_config
debug3: /etc/ssh/ssh_config line 55: Including file /etc/ssh/ssh_config.d/50-redhat.conf depth 0
debug1: Reading configuration data /etc/ssh/ssh_config.d/50-redhat.conf
debug2: checking match for 'final all' host gitlab.com originally gitlab.com
debug3: /etc/ssh/ssh_config.d/50-redhat.conf line 3: not matched 'final'
debug2: match not found
debug3: /etc/ssh/ssh_config.d/50-redhat.conf line 5: Including file /etc/crypto-policies/back-ends/openssh.config depth 1 (parse only)
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
debug3: gss kex names ok: [gss-curve25519-sha256-,gss-nistp256-sha256-,gss-group14-sha256-,gss-group16-sha512-]
debug3: kex names ok: [curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512]
debug1: configuration requests final Match pass
debug1: re-parsing configuration
debug1: Reading configuration data /etc/ssh/ssh_config
debug3: /etc/ssh/ssh_config line 55: Including file /etc/ssh/ssh_config.d/50-redhat.conf depth 0
debug1: Reading configuration data /etc/ssh/ssh_config.d/50-redhat.conf
debug2: checking match for 'final all' host gitlab.com originally gitlab.com
debug3: /etc/ssh/ssh_config.d/50-redhat.conf line 3: matched 'final'
debug2: match found
debug3: /etc/ssh/ssh_config.d/50-redhat.conf line 5: Including file /etc/crypto-policies/back-ends/openssh.config depth 1
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
debug3: gss kex names ok: [gss-curve25519-sha256-,gss-nistp256-sha256-,gss-group14-sha256-,gss-group16-sha512-]
debug3: kex names ok: [curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512]
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts' -> '/home/username/.ssh/known_hosts'
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts2' -> '/home/username/.ssh/known_hosts2'
debug2: resolving "gitlab.com" port 22
debug2: ssh_connect_direct
debug1: Connecting to gitlab.com [172.65.251.78] port 22.
debug1: Connection established.
debug1: identity file /home/username/.ssh/id_rsa type 0
debug1: identity file /home/username/.ssh/id_rsa-cert type -1
debug1: identity file /home/username/.ssh/id_dsa type -1
debug1: identity file /home/username/.ssh/id_dsa-cert type -1
debug1: identity file /home/username/.ssh/id_ecdsa type -1
debug1: identity file /home/username/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/username/.ssh/id_ecdsa_sk type -1
debug1: identity file /home/username/.ssh/id_ecdsa_sk-cert type -1
debug1: identity file /home/username/.ssh/id_ed25519 type -1
debug1: identity file /home/username/.ssh/id_ed25519-cert type -1
debug1: identity file /home/username/.ssh/id_ed25519_sk type -1
debug1: identity file /home/username/.ssh/id_ed25519_sk-cert type -1
debug1: identity file /home/username/.ssh/id_xmss type -1
debug1: identity file /home/username/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.4
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2p2 Ubuntu-4ubuntu2.8
debug1: match: OpenSSH_7.2p2 Ubuntu-4ubuntu2.8 pat OpenSSH_7.0*,OpenSSH_7.1*,OpenSSH_7.2*,OpenSSH_7.3*,OpenSSH_7.4*,OpenSSH_7.5*,OpenSSH_7.6*,OpenSSH_7.7* compat 0x04000002
debug2: fd 4 setting O_NONBLOCK
debug1: Authenticating to gitlab.com:22 as 'git'
debug3: hostkeys_foreach: reading file "/home/username/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/username/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from gitlab.com
debug3: order_hostkeyalgs: have matching best-preference key type ecdsa-sha2-nistp256-cert-v01@openssh.com, using HostkeyAlgorithms verbatim
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,ext-info-c
debug2: host key algorithms: ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,sk-ecdsa-sha2-nistp256-cert-v01@openssh.com,ssh-ed25519-cert-v01@openssh.com,sk-ssh-ed25519-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,sk-ecdsa-sha2-nistp256@openssh.com,ssh-ed25519,sk-ssh-ed25519@openssh.com,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: aes256-gcm@openssh.com,chacha20-poly1305@openssh.com,aes256-ctr,aes128-gcm@openssh.com,aes128-ctr
debug2: ciphers stoc: aes256-gcm@openssh.com,chacha20-poly1305@openssh.com,aes256-ctr,aes128-gcm@openssh.com,aes128-ctr
debug2: MACs ctos: hmac-sha2-256-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha2-256,hmac-sha1,umac-128@openssh.com,hmac-sha2-512
debug2: MACs stoc: hmac-sha2-256-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha2-256,hmac-sha1,umac-128@openssh.com,hmac-sha2-512
debug2: compression ctos: none,zlib@openssh.com,zlib
debug2: compression stoc: none,zlib@openssh.com,zlib
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256@libssh.org,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: ciphers stoc: chacha20-poly1305@openssh.com,aes128-ctr,aes192-ctr,aes256-ctr,aes128-gcm@openssh.com,aes256-gcm@openssh.com
debug2: MACs ctos: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: umac-64-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,zlib@openssh.com
debug2: compression stoc: none,zlib@openssh.com
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug1: kex: algorithm: curve25519-sha256@libssh.org
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: aes256-gcm@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: aes256-gcm@openssh.com MAC: <implicit> compression: none
debug1: kex: curve25519-sha256@libssh.org need=32 dh_need=32
debug1: kex: curve25519-sha256@libssh.org need=32 dh_need=32
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:HbW3g8zUjNSksFbqTiUWPWg2Bq1x8xdGUrliXFzSnUw
debug3: hostkeys_foreach: reading file "/home/username/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/username/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from gitlab.com
debug3: hostkeys_foreach: reading file "/home/username/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/username/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from 172.65.251.78
debug1: Host 'gitlab.com' is known and matches the ECDSA host key.
debug1: Found key in /home/username/.ssh/known_hosts:1
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey out after 4294967296 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey in after 4294967296 blocks
debug1: Will attempt key: /home/username/.ssh/id_rsa RSA SHA256:xxxxx agent
debug1: Will attempt key: /home/username/.ssh/id_dsa 
debug1: Will attempt key: /home/username/.ssh/id_ecdsa 
debug1: Will attempt key: /home/username/.ssh/id_ecdsa_sk 
debug1: Will attempt key: /home/username/.ssh/id_ed25519 
debug1: Will attempt key: /home/username/.ssh/id_ed25519_sk 
debug1: Will attempt key: /home/username/.ssh/id_xmss 
debug2: pubkey_prepare: done
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /home/username/.ssh/id_rsa RSA SHA256:xxxxx agent
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 60
debug1: Server accepts key: /home/username/.ssh/id_rsa RSA SHA256:xxxxx agent
debug3: sign_and_send_pubkey: RSA SHA256:xxxxx
debug3: sign_and_send_pubkey: signing using rsa-sha2-256 SHA256:xxxxx
debug3: send packet: type 50
debug3: receive packet: type 52
debug1: Authentication succeeded (publickey).
Authenticated to gitlab.com ([172.65.251.78]:22).
debug2: fd 5 setting O_NONBLOCK
debug2: fd 7 setting O_NONBLOCK
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug3: send packet: type 90
debug1: Requesting no-more-sessions@openssh.com
debug3: send packet: type 80
debug1: Entering interactive session.
debug1: pledge: network
debug3: receive packet: type 80
debug1: client_input_global_request: rtype hostkeys-00@openssh.com want_reply 0
debug3: receive packet: type 4
debug1: Remote: Forced command.
debug3: receive packet: type 4
debug1: Remote: Port forwarding disabled.
debug3: receive packet: type 4
debug1: Remote: X11 forwarding disabled.
debug3: receive packet: type 4
debug1: Remote: Agent forwarding disabled.
debug3: receive packet: type 4
debug1: Remote: PTY allocation disabled.
debug3: receive packet: type 4
debug1: Remote: Forced command.
debug3: receive packet: type 4
debug1: Remote: Port forwarding disabled.
debug3: receive packet: type 4
debug1: Remote: X11 forwarding disabled.
debug3: receive packet: type 4
debug1: Remote: Agent forwarding disabled.
debug3: receive packet: type 4
debug1: Remote: PTY allocation disabled.
debug3: receive packet: type 91
debug2: channel_input_open_confirmation: channel 0: callback start
debug2: fd 4 setting TCP_NODELAY
debug3: ssh_packet_set_tos: set IP_TOS 0x20
debug2: client_session2_setup: id 0
debug1: Sending environment.
debug3: Ignored env IMSETTINGS_INTEGRATE_DESKTOP
debug3: Ignored env SHELL
debug3: Ignored env LSCOLORS
debug3: Ignored env SESSION_MANAGER
debug3: Ignored env WINDOWID
debug3: Ignored env COLORTERM
debug3: Ignored env XDG_CONFIG_DIRS
debug3: Ignored env XDG_SESSION_PATH
debug3: Ignored env HISTCONTROL
debug3: Ignored env XDG_MENU_PREFIX
debug3: Ignored env HISTSIZE
debug3: Ignored env HOSTNAME
debug3: Ignored env GIT_SSH_COMMAND
debug3: Ignored env SSH_AUTH_SOCK
debug1: Sending env XMODIFIERS = @im=none
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env DESKTOP_SESSION
debug3: Ignored env SSH_AGENT_PID
debug3: Ignored env EDITOR
debug3: Ignored env XDG_SEAT
debug3: Ignored env PWD
debug3: Ignored env LOGNAME
debug3: Ignored env XDG_SESSION_DESKTOP
debug3: Ignored env XDG_SESSION_TYPE
debug3: Ignored env PANEL_GDK_CORE_DEVICE_EVENTS
debug3: Ignored env XAUTHORITY
debug3: Ignored env XDG_GREETER_DATA_DIR
debug3: Ignored env GIT_EXEC_PATH
debug3: Ignored env HOME
debug3: Ignored env SSH_ASKPASS
debug1: Sending env LANG = it_IT.utf8
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env LS_COLORS
debug3: Ignored env XDG_CURRENT_DESKTOP
debug3: Ignored env VTE_VERSION
debug3: Ignored env XDG_SEAT_PATH
debug3: Ignored env CLICOLOR
debug3: Ignored env IMSETTINGS_MODULE
debug3: Ignored env MOZ_GMP_PATH
debug3: Ignored env XDG_SESSION_CLASS
debug3: Ignored env TERM
debug3: Ignored env LESSOPEN
debug3: Ignored env USER
debug3: Ignored env DISPLAY
debug3: Ignored env SHLVL
debug3: Ignored env QT_IM_MODULE
debug3: Ignored env XDG_VTNR
debug3: Ignored env XDG_SESSION_ID
debug3: Ignored env XDG_RUNTIME_DIR
debug1: Sending env LC_ALL = C
debug2: channel 0: request env confirm 0
debug3: send packet: type 98
debug3: Ignored env KDEDIRS
debug3: Ignored env XDG_DATA_DIRS
debug3: Ignored env PATH
debug3: Ignored env GDMSESSION
debug3: Ignored env DBUS_SESSION_BUS_ADDRESS
debug3: Ignored env MAIL
debug3: Ignored env OLDPWD
debug1: Sending command: git-upload-pack 'username/reponame.git'
debug2: channel 0: request exec confirm 1
debug3: send packet: type 98
debug2: channel_input_open_confirmation: channel 0: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel 0: rcvd adjust 2097152
debug3: receive packet: type 99
debug2: channel_input_status_confirm: type 99 id 0
debug2: exec request accepted on channel 0
debug2: channel 0: read<=0 rfd 5 len 0
debug2: channel 0: read failed
debug2: channel 0: chan_shutdown_read (i0 o0 sock -1 wfd 5 efd 8 [write])
debug2: channel 0: input open -> drain
debug2: channel 0: ibuf empty
debug2: channel 0: send eof
debug3: send packet: type 96
debug2: channel 0: input drain -> closed
debug3: receive packet: type 98
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug3: receive packet: type 96
debug2: channel 0: rcvd eof
debug2: channel 0: output open -> drain
debug2: channel 0: obuf empty
debug2: channel 0: chan_shutdown_write (i3 o1 sock -1 wfd 7 efd 8 [write])
debug2: channel 0: output drain -> closed
debug3: receive packet: type 97
debug2: channel 0: rcvd close
debug3: channel 0: will not send data after close
debug2: channel 0: almost dead
debug2: channel 0: gc: notify user
debug2: channel 0: gc: user detached
debug2: channel 0: send close
debug3: send packet: type 97
debug2: channel 0: is dead
debug2: channel 0: garbage collecting
debug1: channel 0: free: client-session, nchannels 1
debug3: channel 0: status: The following connections are open:
  #0 client-session (t4 r0 i3/0 o3/0 e[write]/0 fd -1/-1/8 sock -1 cc -1)

debug3: send packet: type 1
debug1: fd 0 clearing O_NONBLOCK
debug3: fd 1 is not O_NONBLOCK
Transferred: sent 3744, received 3988 bytes, in 0.6 seconds
Bytes per second: sent 6099.2, received 6496.7
debug1: Exit status 0

I’m having the same issue, it looks like we’re hitting the following bug:

The update at https://bodhi.fedoraproject.org/updates/FEDORA-2020-413ab3bca3 fixes the problem for me.

Thanks!

I added

Host gitlab.com
PubkeyAcceptedKeyTypes=+ssh-rsa

to ~/.ssh/config and now the connection works again.

I will wait for the fix to reach the Fedora Updates repository.