Gitlab not working with SSH Keys

Providing that you have loaded your private key on your client, then it sounds like this might be a permissions issue on the 'git' user home directory and .ssh directory.

Please try changing your /home/git directory to a mask of 0711:

chmod 0711 /home/git

Ensure the /home/git/.ssh directory has a mask of 0700:

chmod 0700 /home/git/.ssh

Ensure the /home/git/.ssh/authorized_keys file has a mask of 0600:

chmod 0600 /home/git/.ssh/authorized_keys

Replace /home/git with whatever your home directory for the 'git' user is, if it was different in the tutorial. If it's not permissions, then please let comment and we'll see what else might be the issue.