Calendar Problems

Fix Exchange Room Request Sent to Uninvited User | Calendar Troubleshooting

Natalie Taylor Sep 27, 2026 869 views

Question details

An Exchange room reservation request is being forwarded to an uninvited colleague, and there are synchronization inconsistencies between Outlook and Teams.

How to Fix an Exchange Room Request Sent to an Uninvited User

Product: Microsoft Exchange
Device & OS: not provided
Scenario: A user is booking a room mailbox using Microsoft Exchange, but the meeting request routes to a user not on the attendee list.
Observed behavior: The room meeting request is unexpectedly sent to an uninvited user. Additionally, the booking status appears declined in Teams but reserved in Outlook, showing inconsistent calendar information.

Before you start

Ensure you have Microsoft 365 Exchange Administrator or Global Administrator privileges to run PowerShell cmdlets and verify the room mailbox settings.

Solution 1Recommended

Review Calendar Processing Settings via Exchange PowerShell

Use this solution to verify how the room mailbox handles incoming meeting requests and check if an automatic delegate is unintentionally configured.

Room mailboxes usually process requests automatically based on predefined configurations. Incorrect processing settings or hidden delegates can cause the request to be forwarded to an unauthorized or uninvited user.

Connect to Exchange Online

Open PowerShell as an administrator and connect to your Exchange Online environment using the appropriate administrative credentials.

Run Get-CalendarProcessing

Execute the command: Get-CalendarProcessing -Identity 'RoomMailboxName' to retrieve the current calendar settings for the affected room.

Check AutomateProcessing and Delegates

Review the 'AutomateProcessing' value (it should typically be AutoAccept) and verify the 'ResourceDelegates' parameter to ensure no uninvited users are listed as delegates who receive forwarded requests.

Review External Message Policies

Check the 'ProcessExternalMeetingMessages' flag to see if the room is properly configured to handle or reject external booking requests.

Review Calendar Processing Settings via Exchange PowerShell

Configuration Check: If you find an unexpected user in the ResourceDelegates list, removing them will stop the requests from being forwarded to that user.

Solution 2

Verify Mailbox Permissions and Mail Flow Rules

Use this step to rule out any manual inbox rules, mail-flow rules, or unauthorized mailbox permissions that might be forwarding the emails.

Solution 3

Resolve Inconsistent Outlook and Teams Bookings

Address the synchronization issue where a meeting shows as reserved in Outlook but declined in Microsoft Teams.

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Frequently Asked Questions

Why does Microsoft Teams show my room booking as declined while Outlook shows it as reserved?

This synchronization issue often occurs due to cached data on the local client or a delay in processing between Exchange Online and Teams. It can also happen if the meeting violates a room booking policy (like exceeding the maximum duration); Teams may sync the decline immediately, while Outlook displays outdated cached information.

What does the Get-CalendarProcessing cmdlet do?

It is an Exchange PowerShell command used by administrators to view the calendar processing policies, delegate configurations, and auto-accept settings for resource mailboxes, which helps diagnose unauthorized forwarding or auto-decline issues.

How do delegates affect Exchange room mailboxes?

If a user is assigned as a delegate for a room mailbox, Exchange will automatically forward incoming meeting requests to that user so they can manually approve or decline the booking. This often explains why an uninvited user unexpectedly receives room reservation requests.

Outlook & Email Problems