Thank you for all attempts. I did talk to them, but they weren't much help
either to pinpoint what happened.

"Brian Tillman" wrote:

ChristyL wrote:

Exchange.

While I've seen multiple reports about this with Exchange mailboxes and
while I can think of several things that might cause it, I don't have a
definitive answer. It's because of something happening on the Exchange
server, though, so were I you, I'd be speaking to the Exchange admins.
--
Brian Tillman [MVP-Outlook]