False 554 5.2.2 mailbox full error

[bigmaneric973]

I have a user that randomly has email rejected with this error: 554 5.2.2 mailbox full error. He is using about 30% of space. We have made sure that all deleted items are permanently deleted. What I can't seem to figure out is any pattern to the issue. As an example I sent a calendar invite and it went through. A few minutes later I cancelled the invite and my cancellation was returned due to this error.

THanks for the help

[#2]

It's possible it's the recoverable items folder at the limit https://learn.microsoft.com/en-us/exchange/security-and-compliance/recoverable-items-folder/recovera...

[#3]

We have already gone through this step. We even uninstalled Office 365 as a whole and reinstalled it and the problem still exists.

[#4]

We have found a pattern. It appears to happen when a calendar change is proposed. If we change a meeting or try to cancel a meeting that is when the error occurs. Very strange at this point.

Thank you.

[#5]

perhaps you can check the mailbox folder statistics on user, this might be related to mailbox quota fully utilized.

[#6]

We believe we need to flush the deleted appointments from the calendar. They have done this in the past and they are looking for those commands. I do show that there are messages being held there. In the errors on Sync show more messages on the server than in outlook.

Thank you.