Microsoft Teams Chat Access Impacted via FONE Reverse Proxy

Update timeline

1. investigating Nov 07, 2025, 11:52 PM UTC

   Customer Impact: Customers may experience issues using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is actively investigating the problem. As a temporary workaround, customers may update their policy to set Microsoft Office applications to Direct. We will provide the next update by 06:00 UTC.

2. investigating Nov 08, 2025, 08:24 AM UTC

   Customer Impact: Customers may experience issues using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is continuing to work actively on investigating the issue. As a temporary workaround, customers may update their policy to set Microsoft Office applications to Direct. We will provide the next update by 14:00 UTC.

3. investigating Nov 08, 2025, 11:52 AM UTC

   We are continuing to investigate this issue.

4. investigating Nov 08, 2025, 02:00 PM UTC

   Customer Impact: Customers may experience issues using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is continuing to work actively on investigating the issue. As a temporary workaround, customers may update their policy to set Microsoft Office applications to Direct. We will provide the next update by 20:00 UTC.

5. investigating Nov 08, 2025, 08:00 PM UTC

   Customer Impact: Customers may experience issues using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is continuing to work actively on investigating the issue. As a temporary workaround, customers may update their policy to set Microsoft Office applications to Direct. We will provide the next update by 02:00 UTC.

6. investigating Nov 09, 2025, 02:03 AM UTC

   Customer Impact: Customers may experience issues using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is continuing to work actively on investigating the issue. As a temporary workaround, customers may update their policy to set Microsoft Office applications to Direct. We will provide the next update by 10:00 UTC.

7. investigating Nov 09, 2025, 10:04 AM UTC

   Customer Impact: Customers may experience issues using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is continuing to work actively on investigating the issue. As a temporary workaround, customers may update their policy to set Microsoft Office applications to Direct. We will provide the next update by 16:00 UTC.

8. investigating Nov 09, 2025, 04:26 PM UTC

   Customer Impact: Customers may experience issues using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is continuing to work actively on investigating the issue. continues to work on it 24/7 to find a resolution. As a temporary workaround, customers may update their policy to set Microsoft Office applications to Direct. We will provide the next update by 01:00 UTC.

9. investigating Nov 10, 2025, 03:51 AM UTC

   Customer Impact: Customers may experience issues using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is continuing to work actively on investigating the issue. continues to work on it 24/7 to find a resolution. As a temporary workaround, customers may update their policy to set Microsoft Office applications to Direct. We will provide the next update by 10:00 UTC.

10. investigating Nov 10, 2025, 10:04 AM UTC

    Customer Impact: Customers may experience issues using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is continuing to work actively on investigating the issue. continues to work on it 24/7 to find a resolution. As a temporary workaround, customers may update their policy to set Microsoft Office applications to Direct. We will provide the next update by 20:00 UTC.

11. investigating Nov 10, 2025, 08:17 PM UTC

    Customer Impact: Customers may experience issues using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is continuing to work actively on investigating the issue. continues to work on it 24/7 to find a resolution. As a temporary workaround, customers may update their policy to set Microsoft Office applications to Direct. We will provide the next update by 02:00 UTC.

12. investigating Nov 11, 2025, 03:32 AM UTC

    Customer Impact: Customers may experience issues using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is continuing to work actively on investigating the issue. continues to work on it 24/7 to find a resolution. As a temporary workaround, customers may update their policy to set Microsoft Office applications to Direct. We will provide the next update by 12:00 UTC.

13. investigating Nov 11, 2025, 01:37 PM UTC

    Customer Impact: Customers may experience issues while using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is actively investigating the issue 24x7 and working to trace the error message to its source. We are also exploring alternative solutions and potential workarounds. As a temporary mitigation to alleviate the issue while we work toward a permanent resolution, customers may update their policy settings to configure Microsoft Office applications to Direct mode. We will provide the next update by 23:00 UTC.

14. investigating Nov 11, 2025, 11:18 PM UTC

    Customer Impact: Customers may experience issues while using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is actively investigating the issue 24x7 and working to trace the error message to its source. We are also exploring alternative solutions and potential workarounds. As a temporary mitigation to alleviate the issue while we work toward a permanent resolution, customers may update their policy settings to configure Microsoft Office applications to Direct mode. We will provide the next update by 05:00 UTC.

15. investigating Nov 12, 2025, 07:07 AM UTC

    Customer Impact: Customers may experience issues while using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is actively investigating the issue 24x7 and working to trace the error message to its source. We are also exploring alternative solutions and potential workarounds. As a temporary mitigation to alleviate the issue while we work toward a permanent resolution, customers may update their policy settings to configure Microsoft Office applications to Direct mode. We will provide the next update by 16:00 UTC.

16. investigating Nov 12, 2025, 05:38 PM UTC

    Customer Impact: Customers may experience issues while using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is actively investigating the issue 24x7 and working to trace the error message to its source. We are also exploring alternative solutions and potential workarounds. As a temporary mitigation to alleviate the issue while we work toward a permanent resolution, customers may update their policy settings to configure Microsoft Office applications to Direct mode. We will provide the next update by 00:00 UTC.

17. investigating Nov 13, 2025, 12:28 AM UTC

    Customer Impact: Customers may experience issues while using the Microsoft Teams chat feature through the FONE reverse proxy. Description: We are currently experiencing an issue affecting access to Microsoft Teams chat when accessed through the browser via the FONE CASB reverse proxy. This issue does not impact users who are using the Forcepoint Endpoint Agent. Our engineering team is actively investigating the issue 24x7 and working to trace the error message to its source. We are also exploring alternative solutions and potential workarounds. As a temporary mitigation to alleviate the issue while we work toward a permanent resolution, customers may update their policy settings to configure Microsoft Office applications to Direct mode. We will provide the next update by 06:00 UTC.

18. investigating Nov 13, 2025, 07:37 AM UTC

    Customer Impact: Few of our customers may experience challenges while accessing Microsoft Team's chat feature via the Teams web application while going through Forcepoint's reverse proxy (CASB) service. All functionalities of Microsoft Teams are fully accessible if customers are using desktop application. The impact of this incident remains restricted to customers using Teams via a web application. No other application is impacted, and the issue does not impact customers who are using the Forcepoint Endpoint Agent. Description: Our engineering team is actively investigating the issue 24x7 and working to trace the error message to its source. Forcepoint has also identified possible work-around for the on-going issue and are working with affected customers to deploy the same. The work-around ensures that chat functionality is restored without having to bypass our proxy. We will provide the next update by 17:00 UTC.

19. investigating Nov 13, 2025, 05:38 PM UTC

    Customer Impact: Few of our customers may experience challenges while accessing Microsoft Team's chat feature via a browser while going through Forcepoint's reverse proxy (CASB) service. All functionalities of Microsoft Teams are fully accessible if customers are using desktop application. The impact of this incident remains restricted to customers using Teams via a browser. No other application is impacted, and the issue does not impact customers who are using the Forcepoint Endpoint Agent. Description: Forcepoint continues to investigate the problem and can confirm that the impact of the issue remains extremely limited. We have identified viable work-around for the situation, and are working with affected customers to ensure their connectivity is restored without bypassing our proxy solution. Access to all other applications remain fully operations via Forcepoint's CASB solution.

20. investigating Nov 14, 2025, 06:22 PM UTC

    Customer Impact: A Few of our customers may experience challenges while accessing Microsoft Teams' chat feature via a browser while going through Forcepoint's reverse proxy (CASB) service. All functionalities of Microsoft Teams are fully accessible if customers are using the desktop application. The impact of this incident remains restricted to customers using Teams via a browser. No other application is impacted, and the issue does not impact customers who are using the Forcepoint Endpoint Agent. Description: Forcepoint continues to investigate the problem and can confirm that the impact of the issue remains extremely limited. We have identified a viable workaround for the situation and are working with affected customers to ensure their connectivity is restored without bypassing our proxy solution. Access to all other applications remains fully operational via Forcepoint's CASB solution.

21. investigating Nov 17, 2025, 04:25 AM UTC

    Customer Impact: A Few of our customers may experience challenges while accessing Microsoft Teams' chat feature via a browser while going through Forcepoint's reverse proxy (CASB) service. All functionalities of Microsoft Teams are fully accessible if customers are using the desktop application. The impact of this incident remains restricted to customers using Teams via a browser. No other application is impacted, and the issue does not impact customers who are using the Forcepoint Endpoint Agent. Description: Forcepoint continues to investigate the problem and can confirm that the impact of the issue remains extremely limited. We have identified a viable workaround for the situation and are working with affected customers to ensure their connectivity is restored without bypassing our proxy solution. Access to all other applications remains fully operational via Forcepoint's CASB solution.

22. investigating Nov 18, 2025, 06:29 AM UTC

    Customer Impact: A Few of our customers may experience challenges while accessing Microsoft Teams' chat feature via a browser while going through Forcepoint's reverse proxy (CASB) service. All functionalities of Microsoft Teams are fully accessible if customers are using the desktop application. The impact of this incident remains restricted to customers using Teams via a browser. No other application is impacted, and the issue does not impact customers who are using the Forcepoint Endpoint Agent. Description: Forcepoint continues to investigate the problem and can confirm that the impact of the issue remains extremely limited. We have identified a viable workaround for the situation and are working with affected customers to ensure their connectivity is restored without bypassing our proxy solution. Access to all other applications remains fully operational via Forcepoint's CASB solution.

23. investigating Nov 18, 2025, 08:30 PM UTC

    Customer Impact: A few of our customers may experience challenges when accessing Microsoft Teams' chat feature via a browser while using Forcepoint's reverse proxy (CASB) service. All functionalities of Microsoft Teams are fully accessible when customers use the desktop application. The impact of this incident is limited to customers using Teams through a browser. No other application is impacted, and the issue does not affect customers who are using the Forcepoint Endpoint Agent. Description: Forcepoint continues to investigate the problem and can confirm that the impact of the issue remains extremely limited. We have identified a viable workaround for the situation and are working with affected customers to ensure their connectivity is restored without bypassing our proxy solution. Access to all other applications remains fully operational via Forcepoint's CASB solution.

24. identified Nov 19, 2025, 08:15 PM UTC

    Customer Impact: A few of our customers may experience challenges when accessing Microsoft Teams' chat feature via a browser while using Forcepoint's reverse proxy (CASB) service. All functionalities of Microsoft Teams remain fully accessible when using the desktop application. The impact is limited to customers using Teams through a browser. No other application is impacted, and customers using the Forcepoint Endpoint Agent are unaffected. Current Status & Next Steps: Forcepoint identified the Reverse Proxy code paths impacted by Microsoft Teams changes, causing the Teams Chat feature to fail, and is currently developing a fix. Access to all other applications remains fully operational via Forcepoint's CASB solution.

25. identified Nov 20, 2025, 09:01 AM UTC

    Customer Impact: A few of our customers may experience challenges when accessing Microsoft Teams' chat feature via a browser while using Forcepoint's reverse proxy (CASB) service. All functionalities of Microsoft Teams remain fully accessible when using the desktop application. The impact is limited to customers using Teams through a browser. No other application is impacted, and customers using the Forcepoint Endpoint Agent are unaffected. Current Status & Next Steps: Forcepoint identified the Reverse Proxy code paths impacted by Microsoft Teams changes, causing the Teams Chat feature to fail, We are testing the identified fix in the QA environment and will be deploying to production once the testing process concludes.

26. identified Nov 21, 2025, 07:58 AM UTC

    Customer Impact: A few of our customers may experience challenges when accessing Microsoft Teams' chat feature via a browser while using Forcepoint's reverse proxy (CASB) service. All functionalities of Microsoft Teams remain fully accessible when using the desktop application. The impact is limited to customers using Teams through a browser. No other application is impacted, and customers using the Forcepoint Endpoint Agent are unaffected. Current Status & Next Steps: Forcepoint identified the Reverse Proxy code paths impacted by Microsoft Teams changes, causing the Teams Chat feature to fail, We are testing the identified fix in the QA environment and will be deploying to production once the testing process concludes.

27. identified Nov 22, 2025, 03:44 PM UTC

    Customer Impact: A few of our customers may experience challenges when accessing Microsoft Teams' chat feature via a browser while using Forcepoint's reverse proxy (CASB) service. All functionalities of Microsoft Teams remain fully accessible when using the desktop application. The impact is limited to customers using Teams through a browser. No other application is impacted, and customers using the Forcepoint Endpoint Agent are unaffected. Current Status & Next Steps: Forcepoint identified the Reverse Proxy code paths impacted by Microsoft Teams changes, causing the Teams Chat feature to fail, We are testing the identified fix in the QA environment and will be deploying to production once the testing process concludes.

28. resolved Nov 23, 2025, 05:09 PM UTC

    Customer Impact: A few of our customers may experience challenges when accessing Microsoft Teams' chat feature via a browser while using Forcepoint's reverse proxy (CASB) service. All functionalities of Microsoft Teams remain fully accessible when using the desktop application. The impact is limited to customers using Teams through a browser. No other application is impacted, and customers using the Forcepoint Endpoint Agent are unaffected. Current Status: The issue has been resolved, and normal functionality has been restored. A simple browser refresh is required for the fix to take effect.