My wife and I ran into something like that. The problem was on the rented server end. If you are the ones renting the server contact the server company. If another friend is renting the server and letting you use it too then your friend will have to make that contact. Sometimes it just takes the server providers time to do maintenance or to upload a recent patch. Its usually fixed by most server providers in 24 hours without jogging their elbows.

It could even be caused by an OS update to the server providers systems and be outside their control.