
As part of our new Outlook Room reservation project (automated meeting room reservations using PowerApps and Power Automate), we use a Power Automate flow to create Outlook events and invite business meeting rooms (Exchange resource mailboxes). We use the French Canadian version of Microsoft 365 with A5 licences.
During our pre-launch validation, we observed that room auto-accept notifications are now being sent in English, even though:
The room mailbox regional settings are configured to fr-CA
Organizers are also configured in fr-CA
Time zone is correctly set to Eastern Standard Time
When the room is booked manually via Outlook or OWA, the notifications are sent in French as expected
The issue occurs only when the event is created via Power Automate / API (Create event V4 or Teams “Create a meeting”).
| Item checked | Result |
|---|---|
| Room mailbox regional configuration | fr-CA confirmed ✅ |
| Organizer regional settings | fr-CA confirmed ✅ |
| Manual booking via Outlook/OWA | Notification in French ✅ |
| Booking via Power Automate (Create event V4 / Teams) | Notification in English ❌ |
| Testing in a FR-FR Power Platform environment | No effect ❌ |
| AutoAccept / AutomateProcessing settings | Correct (AutoAccept enabled) ✅ |
In Power Automate, use Create event (V4) or Create a meeting (Teams).
Add a room mailbox configured in fr-CA.
Send the meeting request.
Observe the room’s auto-accept email.
→ The notification is generated in English, unlike Outlook/OWA bookings
It appears that that although the room mailbox is correctly configured in fr-CA, when an event is created via Power Automate or Graph API, Exchange Online interprets the request as coming from an en-US client, causing the automatic response template to fall back to English.
In other words:
Resource mailboxes do not honor their configured locale (fr-CA) when meeting requests come from API/Power Automate, but they do honor it when requests come from Outlook or OWA.
Re-tested multiple room mailboxes and multiple organizers (all fr-CA).
Verified Set-MailboxRegionalConfiguration and Set-CalendarProcessing parameters.
Confirmed AutoAccept is active.
Tested from multiple Power Platform environments (including FR-FR) → no change.
Compared Outlook vs API behavior → only API-triggered notifications are in English.
This flow is part of a major modernization initiative at FSA ULaval.
The linguistic inconsistency (English notifications instead of French) causes:
Confusion for users
Non-compliance with our institution’s communication standards
A blocker for our production deployment
We require a consistent French notification experience for all room bookings.
We would like Microsoft Support to:
Confirm whether this behavior is known or currently under investigation by the Exchange Online or Power Platform team.
Determine whether any recent change in the Graph API or Power Automate Outlook/Teams connectors could affect the locale used by room mailbox auto-responses.
Provide an official clarification on how Exchange determines the language of automatic room replies for API-created events.
Advise on any workaround, fix, or recommended parameter we could apply until a permanent solution is available.
Manual Outlook booking → French notification
Power Automate API booking → English notification
Could you please investigate this issue and provide guidance or next steps?
We are available to perform additional tests or provide flow run data, JSON payloads, or message traces if required.
Thank you.