@tdemin
I'm not sure if you mean "he couldn't ssh" or "why didn't he ssh? he should've done this"
Anyway:
At my university, most programming assignments have the following rule (explicitely mentioned in task description):
The solution must work (and will be checked) on the `students.mimuw.edu.pl` machine.
So all the students, no matter what they use on their computers, are expected to ssh there to test their solutions before submitting, and this is also where the teachers check it.