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snarayanaswamy's avatar
snarayanaswamy
Occasional Reader
Sep 25, 2025

Unable to send pro-active messages to users on Microsoft Teams

I have built an application to send pro-active messages to users on Microsoft Teams. I am using C# Bot Framework SDK. The application is designed to support users from different tenants [Application Type: multi-tenant] and I have tested the same in the past by installing the app to users belonging to a different tenant than that where the Azure Bot Service is hosted and where the App is registered. Please note that the App doesn't require any API permission but just needs to be installed by the user.

After the recent changes made by Microsoft on July 31, 2025, I am no longer able to create an Azure Bot Service having App Type as multi-tenant. We plan to publish this application to the Microsoft Teams store. I got to know from the GitHub Issue - https://github.com/OfficeDev/Microsoft-Teams-Samples/issues/1747 that once the application is certified by Microsoft it will be multi-tenant. Therefore, I created the Azure Bot Service and App Registration with App Type as single-tenant as multi-tenant option was no longer available.

In the single-tenant configuration, I tested it by installing the application to user belong to the same tenant where the Azure Bot service is hosted and the App is registered. The code started to return an unauthorized exception. Neither I was not able to send out a Welcome Adaptive message card when the Bot application was installed by the user nor I was able to send out a pro-active message to the user.

I had raised a question in the Microsoft Learn Question and Answer Forum and was asked by the Moderator to post it as a thread in the Microsoft Tech Community.

I have mentioned the details in the question along with the attempts that I made to resolve the issue. Kindly go through the details mentioned in the question  - https://learn.microsoft.com/en-us/answers/questions/5565284/unable-to-send-pro-active-messages-to-users-on-mic

I’d really appreciate any help or guidance you can provide on resolving this issue. Thank you in advance for your time and support!

1 Reply

  • Kidd_Ip's avatar
    Kidd_Ip
    MVP
    Sep 26, 2025

    May consider this:

     

    How to Fix It
    1. Publish Your App to the Teams App Store
    - Once certified, Microsoft grants your bot multi-tenant access.
    - External users can install it and receive proactive messages.
    - Follow Microsoft’s publishing guide to submit your app.
    2. Use Federated Identity Credentials (FIC)
    - Add an FIC to your bot’s Azure identity.
    - This allows token exchange across tenants using MSAL or Bot Framework REST API.
    3. Handle Tenant-Specific Authentication
    - Use https://login.microsoftonline.com/{TENANT-ID}/oauth2/v2.0/token for token acquisition.
    - Avoid using /common or /botframework.com endpoints—they no longer work for new bots.
    4. Ensure Bot Is Installed by the User
    - Proactive messaging only works if the bot is installed in the user’s Teams client.
    - Use the conversationReference from the installation event to send messages.

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