Sat there, waiting for my invite for the 8UK tourny, and when it came, I clicked 'Accept' in the chat box, only for it to say 'Invite no longer available'. (No I hadn't left it for too long).
But I had a Plan B, I thought I'd catch it out my doing it the old way, through the 'Invites' box on the right, and that along with 'Game Rooms' were blanked out and I couldn't click them .

had same problem

Simple solution, stay away from tournaments!!

Seen loads of these kind of threads, so I guess it happens to people quite a lot.