How to fix "Mailbox info is stale" error on PowerApps

Replace the template’s legacy GetRoomsInRoomList call with GetRoomsInRoomListV2, and pass the exact SMTP address returned by GetRoomListsV2 rather than the previously hard-coded address.^1^

Update and test the Power Fx

Add a temporary button and set its OnSelect property to:

ClearCollect(
    colRoomLists,
    Office365Outlook.GetRoomListsV2().value
);
ClearCollect(
    colRooms,
    Office365Outlook.GetRoomsInRoomListV2(
        First(colRoomLists).Address
    ).value
)

Then:

1. Run the app and inspect colRoomLists under Variables → Collections.
2. Find the updated room list and copy its returned Address value.
3. Replace the template’s old call:

      Office365Outlook.GetRoomsInRoomList(...)
   

   with:

      Office365Outlook.GetRoomsInRoomListV2(
          "<address returned by GetRoomListsV2>"
      ).value
   

The V2 operation expects a room-list address and returns the rooms in that list.^2^ Exchange room lookup likewise uses the room list’s email address, not its display name or an assumed alias.^3^

Since refreshing the connection did not help, there is no need to repeat that step.

If the updated list is absent or V2 still returns MailboxInfoStale

Have an Exchange administrator run these commands in Exchange Online PowerShell:

Get-DistributionGroup -Identity "[Email]" |
    Format-List Name,DisplayName,PrimarySmtpAddress,RecipientTypeDetails

Get-DistributionGroupMember -Identity "[Email]"

Expected results:

• PrimarySmtpAddress is the newly assigned SMTP address.
• RecipientTypeDetails is RoomList.
• The members are room mailboxes.

Microsoft documents room lists as special distribution groups containing room mailboxes and recommends these commands to verify the list and its members.^4^

If RecipientTypeDetails is not RoomList, the object is currently a normal distribution group. For a cloud-only Exchange Online tenant, convert it back:

Set-DistributionGroup -Identity "[Email]" -RoomList

A room list that has reverted to a distribution group is not discoverable as a room list; Microsoft documents checking RecipientTypeDetails and restoring it with Set-DistributionGroup -RoomList.^5^

For a hybrid Exchange deployment, do not run the cloud-only conversion automatically. Verify and correct the authoritative object in the on-premises Exchange Management Shell instead, because room-list management must occur in the appropriate Exchange location.^6^

Interpreting the result

• GetRoomListsV2 returns the new address and GetRoomsInRoomListV2 works: update every old hard-coded address in the app.
• The new address is missing: this is an Exchange room-list configuration or directory consistency issue, not a Power Apps formula issue.
• The new address is returned but the V2 room lookup still gives MailboxInfoStale: provide the failing address, timestamp, environment, and clientRequestId to Microsoft 365 support so the Exchange/connector backend request can be traced.

References

1. Solved: GetRoomsInRoomList - how to use
2. Office365Client.GetRoomsInRoomListAsync(String, CancellationToken) Method-Definition
3. Get room lists by using EWS in Exchange
4. Manage resource mailboxes in Exchange Online
5. An Exchange Online room list isn't viewable in Outlook or OWA
6. Create and manage room mailboxes in Exchange Server