Possible issue with iframe sandboxing or SDK initialization timing in the Teams web client?

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Possible issue with iframe sandboxing or SDK initialization timing in the Teams web client?

Diermeier Lamaralus 120

Created a personal app with configurable tabs using deep links generated via microsoftTeams.tasks.startTask({ url: "https:///tab?context=" }).

Links work from chat but fail when invoked from a message extension (error: "Invalid deep link format" code 800). Context JSON includes theme, entityId, and subEntityId per docs. Manifest version 1.13 with supportsDeepLinks true. Tested URL encoding and query params.

Possible issue with iframe sandboxing or SDK initialization timing in the Teams web client?

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Kha-N 3,100 Microsoft External Staff Moderator

Hi @Diermeier Lamaralus,

Welcome to the Microsoft Q&A forum, and thank you for reaching out to us.

Please correct me if I’m mistaken, but it sounds like your app’s deep link works fine when triggered from Teams web chat, but fails with an "Invalid deep link format" error when invoked from a message extension. You’re wondering whether this issue is caused by iframe sandboxing or SDK initialization timing in the Teams web client.

To assist you better, could you please share your JSON configuration file? Kindly remove any personal or sensitive information before posting.

Also, have you tested this scenario in the Teams desktop client? If so, does the same error occur there?

Looking forward to your response.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Kha-N 3,100 Reputation points Microsoft External Staff Moderator

2025-09-25T08:31:39.78+00:00

Hi @Diermeier Lamaralus,

I hope you're doing well.

It’s been a little while, and I just want to check in on your request.

If you’re available, could you kindly provide any additional details or updates regarding your issue?

Even a brief response would be appreciated, as it will help me assist you more effectively.

Warm thanks.
Kha-N 3,100 Reputation points Microsoft External Staff Moderator

2025-09-29T08:14:05.9033333+00:00

Hi @Diermeier Lamaralus,

I hope you're doing well.

It’s been a while, and I just wanted to check in on your request.

If you have a moment, could you please provide more details about the issue you're experiencing? Even a small piece of information would help me assist you more effectively.

Warm thanks.

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Possible issue with iframe sandboxing or SDK initialization timing in the Teams web client?

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