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Fix Microsoft Viva Actionable Message Buttons Not Working in Outlook

Phi Hung Vo Oct 21, 2026 868 views

Question details

Users are unable to use actionable message buttons (like Done, Approve, or Comment) in Microsoft Viva and Outlook, often encountering signature validation errors.

How to Fix Microsoft Viva Actionable Message Buttons Not Working

Product: Microsoft Outlook
Device & OS: not provided
Scenario: Interacting with Viva actionable message cards in the Outlook reading pane.
Observed behavior: Actionable message buttons fail to respond, do not appear on the web version, or display a 'Failed to validate the signature of actionable message card' error.

Before you start

Before troubleshooting, check your internet connection and verify if the issue persists across both the Outlook desktop application and Outlook on the web.

Solution 1Recommended

Close Open Actionable Message Cards

Resolve rendering conflicts caused by having too many actionable message cards open simultaneously in Outlook.

According to Microsoft support, Outlook can encounter rendering issues and signature validation errors when multiple actionable messages are active at the same time.

Locate open cards

Check your Outlook reading pane and any open standalone email windows for existing actionable message cards.

Close excess cards

Close or navigate away from all other open actionable message cards. Outlook may fail to render buttons if five or more cards are open concurrently.

Retry the action

Return to the specific Viva actionable message you need to interact with and try clicking the action buttons again.

Card Limit: Ensure you never exceed the limit of four simultaneously open actionable message cards to prevent rendering failures.

Solution 2

Update Outlook and Test Across Platforms

Rule out client-specific bugs by verifying the message behavior on different Outlook platforms and ensuring your app is up to date.

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Frequently Asked Questions

Why do I get a 'Failed to validate the signature' error in Outlook?

This error typically occurs when there is a rendering conflict or a security certificate mismatch with the actionable message card. Closing other open actionable cards and updating Outlook usually resolves the issue.

What is the maximum number of actionable messages I can have open?

According to Microsoft Support, Outlook may fail to render actionable messages properly if you have five or more actionable message cards open simultaneously.

Why are the Viva buttons missing in Outlook on the web?

Missing buttons on the web version could be caused by browser cache issues, ad blockers, or temporary Microsoft server outages. Try clearing your browser cache, disabling extensions, or switching to the desktop app to verify.

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