Can't access a hidden mailbox in Outlook after a migration to Office 365 hybrid environment

Dotyczy: Exchange Online


After a migration to Microsoft Office 365, users cannot open a folder or add a hidden mailbox in Outlook. Also, users may receive the following error messages, depending on what they are trying to add or access.

  • Additional mailbox


  • Additional Exchange account


  • Calendar or other folders



This is expected behavior when you try to add a hidden mailbox.


Auto-mapping enables users who have Full Access permissions to access a hidden mailbox. If you migrate from an on-premises environment, refer to the following Microsoft Knowledge Base article for instructions to enable auto-mapping in a hybrid environment:
3080561 Auto-mapping doesn’t work as expected in an Office 365 hybrid environment