thank you for your answer
To 1. the users themselves have assigned the reviewer permissions via Outlook.
To 2. no items were moved to the online archive by the user himself. If so, it was through a retention policy.
He does not have full access rights to the mailboxes.
->"To my knowledge, only by assigning full access permission would give the user access to the archive mailbox."
Since when is it possible to assign full access permissions to individual folders? But as I said, he does not have full access rights. No changes have been made.
I have added three screenshots.
- You can see all the automapped calendar online achrives
- you can see the reviewer permissions
- you can see that there re no fullaccess permissions. only the user himself has full access to his own mailbox.