If you are getting permission denied when working with git on a remote server using a key, this may help.

First test to ensure the key will be accepted by the remote server.

ssh -v git@git.example.com

Look for these lines in the output:

debug1: Next authentication method: publickey
debug1: Offering public key: /home/account/.ssh/example.key
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug1: Authentication succeeded (publickey).

Then check your ~/.ssh/config file. Be sure the user is in the file and matches what worked with the ssh test.

~/.ssh/config

Host git.example.com
    User git
    IdentityFile ~/.ssh/example.key

Now get back to work.

:)