“Debug in Teams (edge)” Opens Random Chat, Desktop Debug Works Fine

[ndamulelonemakh]

Describe the bug

When I launch a “Debug in Teams (edge)” local debug session in VS Code and choose Web preview, Teams uploads the app but then flashes a popup and opens a random existing chat instead of loading my side-loaded app. Previously it would open the Teams web client directly into my bot conversation.

To Reproduce

1. Open your Teams project in VS Code (Using the Teams App template for Python)
2. Press F5 (or click “Debug → Start Debugging”) and select Teams (local).
3. When prompted, pick Web as the preview target.
4. Watch the browser popup flash, then Teams web opens an unrelated chat window.

Expected behavior

After selecting Web preview, the Teams web client should open with my side-loaded app loaded in a conversation pane (ready to chat), not drop me into a random existing chat.

Screenshots

• N/a

VS Code Extension Information (please complete the following information):

• OS: macOS 15.5
• Identifier: teamsdevapp.ms-teams-vscode-extension
• Version: 6.0.2 (Last Updated: 2025-07-02 12:36:59)

CLI Information (please complete the following information):

• OS: macOS 15.5
• CLI Version: @microsoft/teamsfx4.0.0

Additional context

• Desktop preview works correctly every time; only Web preview is broken.
• Verified same M365 account in VS Code and browser, dev tunnel cert trusted, and manifest credentials up to date.

[m365-agent-toolkit-assistant]

👋 Hi @ndamulelonemakh,

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 2 business days

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

This is a known issue: the Teams web client sometimes opens a random chat (or just the Teams welcome page) when debugging or sideloading a Teams app with "Web preview" in VS Code (using Microsoft 365 Agents Toolkit/Teams Toolkit). Desktop preview works, but Web sometimes fails to focus your app/bot.

Relevant findings:

• GitHub: msteams-docs#12798
• Teams web occasionally ignores or mishandles the deep link to your sideloaded app.
• Clearing Teams web cache, using incognito mode, or manually uploading the app may resolve it (but not always).
• Ensure sideloading is enabled, the app manifest is current, and try a private window for web preview.
• Some users report the issue is specific to Mac and/or recent Teams updates.
• Microsoft internal engineering is investigating.

Workarounds:

1. Use Teams desktop for debugging (recommended by Microsoft).
2. Try a different browser/new incognito window.
3. Manually upload your app package in the Teams web client.
4. Keep Teams web (all tabs) closed before F5/debug start.

If persistent, follow or comment on the linked GitHub issue—engineering is tracking this for future fixes.

✨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!

[nliu-ms]

So sorry for the inconvenience @ndamulelonemakh , can you please open an issue for Teams client: https://github.com/MicrosoftDocs/msteams-docs/issues

We already reported this to Teams platform but no progress..

There was an workaround is to manually upload app package from

But recently there's another issue that the upload button is disabled, even when the tenant upload custom app settting is open. It happens for some tenants, not sure if it works for you.

[sayali-MSFT]

@ndamulelonemakh ,Thank you for bringing this issue to our attention. We will look into it and get back to you shortly.

[sayali-MSFT]

@ndamulelonemakh, Thank you for your report! We are currently unable to reproduce the issue you’re experiencing. Could you please provide the following information to help us better assist you?

Error Logs: If available, please share any relevant error logs or messages that you’ve received.

This information will be invaluable in helping us understand the problem and find a solution.