Summary
You can manage RemoteUserMailbox and RemoteSharedMailbox mailbox types through either Exchange Admin Center (EAC) or Exchange Management Shell (EMS). However, the RemoteEquipmentMailbox and RemoteRoomMailbox types could previously be managed only through EMS. Beginning in Microsoft Exchange Server 2019 CU14, both the "equipment" and "room" mailbox types can be managed through EAC also.
Resolution
To fix this issue, install the following cumulative update:
Cumulative Update 14 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019
