Calendar Settings

Question

Calendar Settings

Glenn Maxwell 14,206

Hi All,

I have a shared mailbox, for example, smb1[@]mydomain.com

When someone from our team creates a calendar event or meeting on the shared mailbox calendar, the meeting request appears to require acceptance before it is added to the calendar.

We would like these meeting requests to be automatically accepted/approved and added to the shared mailbox calendar without manual intervention. Is there an Exchange Online/Microsoft 365 configuration that can enable this behavior?

0 comments

Answer accepted by question author

Aetherin 2,505 Independent Advisor

Hi @Glenn Maxwell,

If I understand your scenario correctly, users are creating meetings in their own calendars and inviting ******@mydomain.com as an attendee. You would like the shared mailbox to accept those invitations automatically so that they appear in its calendar.

If so, Exchange Online’s automatic booking functionality is designed for resource mailboxes, such as room or equipment mailboxes. Microsoft documents that Set-CalendarProcessing, including AutomateProcessing AutoAccept, is effective only on resource mailboxes, not standard shared mailboxes. You can find more details in the Microsoft documentation for: Set-CalendarProcessing.

If ******@mydomain.com represents a resource that users need to invite and reserve, an Exchange administrator could consider converting it to an appropriate resource mailbox and then configuring automatic processing. Shared-to-resource conversion is supported through Exchange Online PowerShell. Microsoft provides guidance on both mailbox conversion and resource mailbox management in the following articles:

That said, conversion may not be suitable if the mailbox is intended to remain a traditional shared mailbox or if team members regularly create meetings directly from that mailbox and use it as the meeting organizer.

Also, if users are creating meetings directly in the shared mailbox calendar, those meetings should already be stored in that calendar and should not require the shared mailbox to accept them. In that case, please clarify where the meeting is created and which mailbox appears as the organizer.

Based on the scenario currently described, the Direct to Calendar solution previously suggested by the forum's AI-generated response may not be the best match for this particular use case. Direct to Calendar is designed to automatically add meeting requests from designated senders to recipients' calendars. Its behavior differs from the automatic booking and acceptance functionality available with resource mailboxes.

Please take a look through the information above and see whether it aligns with your current setup and requirements. I hope it provides some useful context and helps point you toward the most appropriate solution for your scenario.

If you have any updates or would like to share additional details about your configuration, please feel free to reply.

Thank you so much for taking the time.

If the answer is helpful, please kindly click "Yes" button below. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in the forum documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

0 comments

2 additional answers

Your answer

Answer 1

Glenn Maxwell 14,206

Do I need to create the following two mail flow rules to automatically accept calendar meeting requests for the shared mailbox? If so, will this configuration work?

Rule 1 – Priority 10
Name: SMB-Rule1

Apply this rule if:
The recipient is smb1[@]mydomain.com

Do the following:
Modify the message properties → Set a message header

Message header:
X-MS-Exchange-Organization-CalendarBooking-Response

Value:
Accept

Rule 2 – Priority 11
Name: SMB-Rule2

Apply this rule if:
The recipient is smb1[@]mydomain.com

Do the following:
Modify the message properties → Set a message header

Message header:
X-MS-Exchange-Organization-CalendarBooking-TriageAction

Value:
MoveToDeletedItems

Should these rules be configured in this order (Priority 10 followed by Priority 11), and will they achieve the desired behavior of automatically accepting the meeting requests and preventing the requests from remaining in the mailbox?

Aetherin 2,505 Reputation points Independent Advisor

2026-09-28T17:55:12.77+00:00
Hi @Glenn Maxwell,

The two headers you listed are associated with Exchange Online's Direct to Calendar feature. The first is used to automatically add the meeting to the recipient's calendar, while the second can be used to move the invitation to Deleted Items after processing to help reduce Inbox clutter.

Regarding rule order, priorities 10 and 11 would generally be acceptable, provided the first rule is not configured to stop the processing of subsequent mail flow rules.

However, Microsoft's documented examples for Direct to Calendar typically scope these rules based on the sender of the meeting request, whereas your proposed configuration scopes them based on the recipient. Before discussing whether this approach is suitable for your scenario, could you clarify whether users are:

Creating meetings from their own mailboxes and inviting ******@mydomain.com as an attendee, or

Creating meetings directly in the shared mailbox calendar, with ******@mydomain.com acting as the organizer?

This distinction is important because Direct to Calendar is designed to add meeting invitations from designated senders directly to recipients' calendars. If the mailbox represents a resource that needs automatic acceptance, conflict checking, booking policies, or similar functionality, a resource mailbox may be a more appropriate solution.

I look forward to your clarification and would be happy to discuss the scenario further once we better understand the intended workflow.
Aetherin 2,505 Reputation points Independent Advisor

2026-09-30T07:25:49.6266667+00:00

Hi @Glenn Maxwell,

Is there any update from you. If yes, please feel free to let me know.

Answer 2

Yes. In Exchange Online, this can be done by using Direct to Calendar mail flow rules.

Direct to Calendar lets designated senders have meeting invitations automatically added to recipients’ calendars without attendee action. It requires two mail flow rules:

A rule that sets the header: X-MS-Exchange-Organization-CalendarBooking-Response: Accept
An optional but recommended rule that sets the header: X-MS-Exchange-Organization-CalendarBooking-TriageAction: MoveToDeletedItems

For the shared mailbox scenario, Microsoft recommends using a dedicated mailbox to send these invitations, and shared mailboxes are supported for that purpose.

In Exchange Online PowerShell, the rules can be created like this:

New-TransportRule -Name "Direct to Calendar response" -From "Direct to Calendar invites" -SetHeaderName "X-MS-Exchange-Organization-CalendarBooking-Response" -SetHeaderValue Accept

New-TransportRule -Name "Direct to Calendar triage action" -From "Direct to Calendar invites" -SetHeaderName "X-MS-Exchange-Organization-CalendarBooking-TriageAction" -SetHeaderValue MoveToDeletedItems

Important behavior notes:

Any meeting invitations from the designated sender mailbox will be automatically added to recipient calendars.
The second rule is optional; without it, meetings are still automatically added, but meeting-related messages can still appear in recipients’ Inboxes.
To verify the setup, send a test meeting invitation from the designated sender mailbox and confirm that it appears automatically in recipients’ calendars.
Acceptance responses are still sent to the designated sender mailbox.

If the goal is specifically for meetings sent from the shared mailbox to be auto-added to attendees’ calendars, this is the supported Exchange Online configuration described in the documentation.

References:

Use mail flow rules to automatically add meetings to calendars in Exchange Online