Calendar says "There was a problem reaching this app"

Question

How do I fix this? I have tried everything to fix the issue.

Answer 1

Dear @Brooke Nicole Male,

Thank you for reaching out to Microsoft Q&A forum.

I understand that you're experiencing an unexpected issue with the Calendar in Teams. As a forum moderator, I genuinely wish I could directly access your account or delve into the backend systems to diagnose and resolve this for you. However, our role here is limited to providing general guidance and solutions that users can apply themselves.

From my research, this type of issue with the 'There was a problem reaching this app' error message in Teams Calendar is typically a failure in the authentication handshake between the Teams client and the Exchange Online backend. This means that even if your credentials are valid, the local token or the hosted JavaScript module may be failing to load correctly.

To help me better understand your situation, could you please share what troubleshooting steps you've already tried?

Since you haven’t specified your account type, I may not be able to provide an exact solution. However, assuming you're using a Work/School account managed by an organization, you may consider the following steps:  

1.Perform a "Deep" Cache Clear

1. Fully close Teams (ensure it is not running in the Task Manager).
2. Press Windows Key + R, paste the following path, and press Enter: %localappdata%\Packages\MSTeams_8wekyb3d8bbwe\LocalCache\Microsoft\MSTeams
3. Delete everything inside this folder.
4. Restart Teams. the app is forced to re-download the Calendar manifest and re-authenticate your Exchange session.

2.Test in Incognito Mode or Web Version

To determine if this issue is specific to your computer or your entire account, perform this test:

• Open a browser in Incognito/Private mode.
• Log in to teams.microsoft.com.
• If the Calendar works here, the problem is strictly a local issue with your desktop software.
• If the error persists in Incognito, this issue is server-side and related to your mailbox permissions.

3.Contact IT admin

If the issue persists, your IT admin can help check the following:

Review the Teams Admin Center for blocked apps, add-ins, or policies affecting Calendar integration.

Confirm that your account license includes full Exchange/Calendar access.

I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this. If none of the above solutions work, let me know in the comments for further investigation. Please note that our initial response does not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution. Thank you for your patience and understanding. I'm looking forward to your reply. 

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