Please improve error message on failing to connect to server

[nrnrnr]

I lost at least a half hour yesterday trying to diagnose a failure to connect to the handin server. I was puzzled because telnet connected to the server just fine. Eventually wireshark confirmed that drracket was exchanging packets and finally I figured out there was a problem with my certificates.

It would be great to have a more specific error message, but just a amllchange would help a lot: instead of "could not connect to the server", how about "could not establish an authenticated connection to the server".

Of course it would be even better if the message could say whether the issue is in the connect(2) call or in the authentication, but at least this way users will have a hint that something other than connect is the problem.

Also, it might be a kind act to alert people that if connection to the server becomes a problem, the source code can be edited to produce a more complete message.