Teams tab app not working in Outlook and Microsoft 365 Copilot on iOS (works on Android)

[shimbaroid]

We are submitting this issue as part of our Microsoft Teams App validation process.
During the review, the Teams App Submission team found that our Teams tab app does not function properly on iOS within the Outlook and Microsoft 365 Copilot apps.
They recommended that we raise a support ticket here for further technical investigation.

I have personally confirmed the following behavior:

Platform	Teams app	Outlook app	Microsoft 365 Copilot app
iOS	✅ Works	❌ Not working	❌ Not working
Android	✅ Works	✅ Works	✅ Works

Observed behavior (on iOS)

When attempting to open the Teams tab app inside Outlook or Microsoft 365 Copilot, the app either:

• Prompts for permissions(OIDC) but remains stuck on the same screen after granting them (no further progress).

Expected behavior

The Teams tab app should open and display its tab content on iOS, just as it does on Android.

Questions

How we can debug this issue effectively on iOS, especially given that the app behaves correctly on Android.

Thank you.

[m365-agent-toolkit-assistant]

👋 Hi @shimbaroid,

Thank you for reporting this issue! We want to let you know that:

⏱️ Our team will personally review your issue
🎯 You can expect a response within 1 business day

✨ This is an AI-generated initial response
🤖 AI-Generated Preliminary Analysis:

This is a known platform issue: Teams tab apps often face authentication (OIDC, MSAL, Graph token) failing on iOS inside Outlook and Copilot, even if they work on Android and in Teams itself.

Immediate debugging steps:

1. Check authentication flow:
   iOS WebView sometimes fails to persist tokens; getAccessToken() may return empty or prompt repeatedly (example issue).
2. Use On-Behalf-Of (OBO) flow for token exchange—see this solution.
3. Update validDomains/webApplicationInfo in manifest (sample fix).
4. Test with latest app versions on all platforms. Sometimes the issue is fixed by app updates.

If you provide these:

• Your development stack (VS Code, Teams Toolkit version)
• manifest and token code snippets

I can help validate and suggest targeted code changes.

✨We'd love your feedback! Please take a moment to fill out our survey.

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Note: This is an automated first response generated by AI. A human team member will review your issue and provide a more detailed response soon. We appreciate your patience!

[Prasad-MSFT]

Hi @shimbaroid, thanks for raising your issue. Could you please let us know whether the solution provided above has addressed your concern? If not, could you please provide the app manifest you are using or the repro video to investigate further?

[shimbaroid]

Thank you for your support. I will try the steps you have suggested.
It may take some time to test them thoroughly, so the process could be long-term.
I appreciate your continued assistance.