Not enough rep to post a comment so I'm writing an answer.

Sounds like you could have an SSH configuration mismatch between your /etc/ssh/sshd_config file on your Pi, and your /etc/ssh/ssh_config file on your Mac.

Can you post the uncommented text from your Pi's sshd_config file, your Mac's ssh_config file, and the ssh_config file from another computer that can successfully connect?

That should give us some starting information to debug what might be going on and I can edit my answer as we go.