Request for git@gitlab.xxx.com password

I am using my company’s internal gitlab server .
While syncing from this server, i get prompt asking for password of
git@gitlab.xxx.com

Facing above issue with a common linux server for my user account.
Other users of the machine are able to sync from gitlab.

If I try to sync from my virtual machine it works.

Note : My SSH keys are added to gitlab account and I have access to the repo’s.

Kindly help to figure out whats missing.

Additional info, 25.06.2017

Non-working case
debug1: Offering RSA public key: /home/user1/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password

Working case
debug1: Offering RSA public key: /home/user1/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug1: Remote: Forced command: /home/git/gitlab-shell/bin/gitlab-shell key-1423

The forced command on SSH server seems not executing when ssh key is offered in the Non-working case.

Hey, Even I am getting the same error. I have followed steps to generate the ssh keys and added public key to my organization gitlab account and when I tried to do clone using ssh it prompts me for password.

Is there anything wrong with my SSH setup? If anyone knows the solution please do let know. I appreciate your time and help

Thanks
Prashanth