I have a number of resource mailboxes which are just used as calendars to book the resource. One of them, a room, has suddenly started only showing it is booked, no details are shown other than it is busy. All others allow all authenticated users to see who has the room booked and how many people are attending. This one room did the same until Monday this week when it decided to be secretive. If you try to look at the meeting, it says you need to ask the mailbox for access, then says you do not have permission to request access. I have checked the AD security settings and see nothing out of place, no differences between this and the other room calendars.
As a work around I logged in as the room and gave a security group containing all staff delegate access which has now allowed everyone to see the details as they should, but this is only a workaround, I need to find what has caused this change and fix it.
Anybody seen this before and have a suggestion for a solution?