Getting this error about 3 out of 4 times when viewing all unread posts:

"The server's resources are temporarily under too high a demand to find all the topics you have not read."

I was getting that late afternoon early evening, seems to have cleared now.

I posted the same distress call in the Server Upgrade thread as I've never had these before so put it down to summat going on.

I replied to another thread about this. It was fixed last night. 

Does seem that way, apologies, I was lost without "all unread posts" and couldn't see the server upgrade thread