When I open the Console from the Fork UI, it does not seem to have ssh-agent running or the SSH key configured and active in Fork is not added to it automatically.
This leads to inconsistent behavior where cloning a repo via SSH using the UI works (via the configured SSH key), but trying to do the same via the Console results in an access error.
A workaround for this is to eval the ssh-agent process in the Console and then manually add the SSH key via ssh-add. Cloning works as expected afterwards, but this needs to be done every time.