"We are searching for a waiter" instead of "...server" is marked as wrong :(
'waiter' is not female!
Nowadays it is, I'm afraid. Added, although I don't like it.
It can be feminine or masculine just like english, and in this case it is feminine plural "We are looking for waitresses"... I think
Unfortunately, "szukać" takes genitive, so it's one waitress in the singular.