We have a user receiving the "temporary mailbox" problem, and we have tried the usual steps, but he's still seeing the message.
"your mailbox has been temporarily moved on MS Exchange Server. a temporary mailbox exists..." 'use temporary' / 'use old data' / 'cancel'.
Re-created outlook profile - no effect.
Uninstalled Office via 365 removal tool
Installed 365 Office 2016
removed / recreated profile again.
checked for any strange add-on's.
started outlook in safe mode, then back to normal mode.
the user's outlook appears to work fine apart from this, but the message continually comes back after dismissing it.
The user has only a single email account within his Mail profile, nothing fancy.
Not sure what to try next!