More than 399 users viewing thread = "forum unavailable" error
 

We had a sponsor with an event last night and they had users who were gettting "forum currently unavailable" errors when viewing the event thread. They also noticed that the amount of users viewing the thread seemed to hang up at 399. We recently moved servers and in the past they have had over 600 users viewing the thread without anyone reporting that error.

Anyone have any ideas? 399 seems like it might be a setting somewhere that was changed.

As always* any help greatly appreciated.