When opening a file in Teams, I get the message "There was a problem reaching this app"

Dear @Li, Jason,

Thank you for posting your question in the Microsoft Q&A forum. 

The error "There was a problem reaching this app" when opening Office files directly in Teams is a symptom we are tracking, and it is likely related to a recent service incident. 

As this incident is very new, it may not yet be reflected on the public Microsoft 365 Service Health Status dashboard. Our engineering teams are undoubtedly already aware and working on a resolution.

Summary for TM1143347:

• Summary generated at: 2025-08-28 08:10:44 AM (+07)
• Last updated at 2025-09004 06:26:34 AM (+07)
• Summary of Impact: The advisory indicates that some users are experiencing difficulties accessing or opening Microsoft Office files directly within Microsoft Teams. This issue affects file types such as Word, Visio, Excel, PowerPoint, Loop, and OneNote. Users can still access these files using 'Open in desktop' or 'Open in browser' options.
• Impact Time: Start: August 27, 2025, 11:48 PM UTC; End: Ongoing
• Scope of Impact: The impact is specific to users attempting to open embedded Microsoft Office files within Microsoft Teams. This includes files in team channels and tabs, affecting less than 50% of users.
• Action Taken: The team identified a recent change in the environment that may have contributed to the issue and reverted it. They are monitoring the situation and reviewing recent changes to isolate the root cause.
• Contributing Factors: The root cause is suspected to be a recent change deployed to a subset of the environment, which is still under investigation.
• Next Steps: The team will continue to monitor the situation and review recent changes to Microsoft Teams or Office services to identify the root cause.

In the meantime, please try these workarounds to access your files: 

1. Use the Teams Web Client: Open your browser and go to Teams on the web. You may find you can open and edit files from there. 
2. Open via OneDrive/SharePoint: Since Teams files are stored in SharePoint or OneDrive, you can navigate to the file’s location in either of these services and open it from there. 

These alternatives should allow you to view and edit your files without interruption. 

Additionally, I recommend reporting this issue directly to the Teams product team by navigating to: Settings > Feedback > Report a problem

Your company’s Global Admins can also report the issue in the Microsoft 365 Admin Center via Service Health, as shown in the screenshot below. 

I completely understand your frustration. Please note that I have escalated this issue to my supervisor. However, as a community moderator, my role is to provide guidance and simple fixes; I do not have the ability to directly influence or expedite the engineering team's troubleshooting process. I appreciate you're understanding on this matter. 

Your patience and understanding are greatly appreciated as Microsoft works to fully resolve this. 

Thank you again for your time and understanding. Hope you have a great day!!

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