Forum not working

Whenever I try to open my forum, which has been running for around three years, all I get is a blank white page with the words:

Critical Error

Could not query config information

I would really appreciate any help as I really don't want to lose the information on the forum. Anyway, here's the link:
http://medievalinop.forumotion.com/

Hi, 

Please see this thread about the on-going issue. https://help.forumotion.com/t141398-critical-error#962749

It has been reported to our technicians and they're working on it.