Microsoft.Mapi.MapiExceptionADPropertyError when trying to open mailbox

Recently I came across an issue, that a restored mailbox was not accessible through Outlook and OWA.

Issue

The error message which appeared was:
InnerException: Microsoft.Mapi.MapiExceptionADPropertyError

After disabling the mailbox, the user was copied and the old user object was not deleted. Now the mailbox was reattached from disconnected mailboxes to the new user object.

Solution

The old and the new user object both had the same legacyExchangeDN set. After clearing the attribut legacyExchangeDN on the old user object which didn’t have a mailbox attached anymore the mailbox was accessible within the next few minutes.