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Hi Eliana,
Thank you for sharing the details of your situation and the troubleshooting you have already completed.
Based on the behavior described, Power Automate appears to be successfully delivering the messages. Since the Adaptive Card renders for your account but other internal recipients receive only the fallback HTML, even when you use a minimal card, the issue may be more closely related to the Outlook Actionable Messages provider registration, originator validation, or Organization-wide activation.
Here are some steps you can try:
1/ Verify the Provider ID used in the card
- Open the Adaptive Card payload in your Power Automate flow and locate the originator property. Confirm that its value exactly matches the Provider ID shown in the approved Organization registration, rather than the Provider ID associated with the separate Test Users registration.
- If these registrations have different Provider IDs, update the payload with the Organization Provider ID, save the flow, and send a new test message.
2/ Confirm the actual sender identity
- Open one of the test messages in Outlook on the web, select More actions (…) > View > View message details, and review the From field in the message headers. Confirm that the sender address shown there exactly matches one of the sender addresses registered for the Organization provider.
- If the flow uses a shared mailbox, Send As, or Send on behalf, verify that the actual sender identity in the headers is the registered address, not only the address displayed in the message.
3/ Run an isolated test
Create a new test flow using:
- The registered sender account
- The approved Organization Provider ID
- A minimal Adaptive Card containing only TextBlock elements
- No actions, inputs, or dynamic content
Send the message to an internal user who has never been included in the Test Users registration, then check the result directly in Outlook on the web. This can help rule out any cached configuration or reference to the previous registration in the existing flow.
For reference, you may find these articles helpful:
- Actionable messages via email developer dashboard guide - Outlook Developer | Microsoft Learn
- Frequently asked questions for Actionable Messages
If the Organization Provider ID and sender identity are correct, but the minimal card still renders only for the Test User, the issue may require service-side investigation. In this case, I recommend asking your organization’s IT administrator to open a support ticket with Microsoft Support through the Microsoft 365 admin center, so the appropriate support team can review the configuration and advise on possible next steps.
When opening the ticket, please provide the relevant Provider IDs, affected sender and recipient addresses, test timestamps, Internet Message IDs, registration screenshots, and Exchange Online settings.
- For detailed guidance on how to open a support ticket with Microsoft Support, please refer to: Get support - Microsoft 365 admin | Microsoft Learn
I hope this information is helpful. Should you have any further questions or need additional assistance, please feel free to share them in the comment below. I'm very happy to help.
I look forward to hearing your thoughts on this.
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