You might try it again on 4022, because I've been messing it randomly over the past couple hours and you might have happened to try while I had it switched to 22 (and i was getting the same apparent hangs as you describe for 22 while it was switched to that).
There should definitely be connectivity on port 4022 - if you do for example
telnet gitlab.common-lisp.net 4022
you will get a connection and can type `GET /` (it will say "invalid ssh identification string" but this should prove that the basic connectivity is there).