I am using the Ubuntu app from the Windows Store (Linux subsystem) and have been using it regularly for awhile. I have it updated to version 18.04 LTS. All of my packages are up-to-date.
I added an SSH key recently for this specific Ubuntu system (I have SSH keys that I use successfully for Windows 10 as well as another Ubuntu Virtual Machine). I followed all of GitLab’s instructions (Use SSH keys to communicate with GitLab | GitLab), as I have done many times in the past.
For some reason, I still get prompted for a password.
Here is the output when I run ssh -Tv git@gitlab.example.com (that’s not my actual host…)
OpenSSH_7.6p1 Ubuntu-4, OpenSSL 1.0.2n 7 Dec 2017
debug1: Reading configuration data /home/chris/.ssh/config
debug1: /home/chris/.ssh/config line 2: Applying options for gitlab.example.com
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to gitlab.example.com [XXX.XXX.XXX.XXX] port 22.
debug1: Connection established.
debug1: identity file /home/chris/.ssh/id_rsa type 0
debug1: key_load_public: No such file or directory
debug1: identity file /home/chris/.ssh/id_rsa-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.6p1 Ubuntu-4
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.4
debug1: match: OpenSSH_7.4 pat OpenSSH* compat 0x04000000
debug1: Authenticating to gitlab.example.com:22 as ‘git’
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: chacha20-poly1305@openssh.com MAC: compression: none
debug1: kex: client->server cipher: chacha20-poly1305@openssh.com MAC: compression: none
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:Qco9zcFOEAUwtnb1c/oATrPTIdToAS/neCP8fmK/hag
debug1: Host ‘gitlab.example.com’ is known and matches the ECDSA host key.
debug1: Found key in /home/chris/.ssh/known_hosts:2
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Next authentication method: gssapi-keyex
debug1: No valid Key exchange context
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available (default cache: FILE:/tmp/krb5cc_1000)debug1: Unspecified GSS failure. Minor code may provide more information
No Kerberos credentials available (default cache: FILE:/tmp/krb5cc_1000)debug1: Next authentication method: publickey
debug1: Offering public key: RSA SHA256:Xl8X1UENFE1CNXU5pUSGw7KFirhXZ+KeNnzCzgKAQUE /home/chris/.ssh/id_rsa
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Next authentication method: password
git@gitlab.example.com’s password:
Would anyone be able to offer any insight or some direction? I’ve tried so many things but am going crazy with this issue. Thank you so much! 
- Chris L