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 do not work - due to missing/invalid settings.

Please go to Administrator->Settings->Rooms to locate the mailbox with missing/invalid settings.

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.