A Room Availability Overview or Meeting Activity Overview does not show any information at all - when showing one of these Displays it shows a black screen.
One or more mailboxes for a room does not work - due to missing/invalid settings,
Please go to Administrator->Settings->Rooms to locate the mailbox with missing/invalid settings
HOW TO SOLVE
Either solve the missing/invalid settings for the affected rooms, or remove the affected room(s) from the Room Availability Overview and Meeting Activity Overview that doesn't work