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Power Automate - Using Flows
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Users with Full Access to a Mailbox are unable to perform approvals from within this Mailbox

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Posted on by 2

I have created a Power Automate flow with an approval. The approval request is sent to a User Mailbox that has multiple people with Full Access rights. When the request is approved by any of these individuals, we receive the error message: 'Failed to validate the signature of the actionable message card.' Does anyone have an idea how we can resolve this?

  • VictorIvanidze Profile Picture
    12,205 on at
    Re: Users with Full Access to a Mailbox are unable to perform approvals from within this Mailbox

    You can try to use this approach: https://ivasoft.com/sendemailwithnativeapproverejectbuttonsflow.shtml

  • lambr2 Profile Picture
    8 on at
    Re: Users with Full Access to a Mailbox are unable to perform approvals from within this Mailbox

    Same problem here. Users have "Send As", "Send on behalf of", and "Full Access" to a user account that is being used as a shared mailbox. When trying to approve from the shared user's mailbox they get the same error message. One solution on a different post was to get them to sign-in as the shared user instead of just accessing the user's mailbox from their own Outlook. I find that solution not feasible as they can read and respond as that user but if they want to approve they need to sign-out of their account, then sign-in as the shared account, make the approval, and then sign-out as the shared, then sign-in as their own account. Way too many steps.

     

    The https://learn.microsoft.com/en-us/outlook/actionable-messages/actionable-messages-faq explicitly says that shared or group mailboxes cannot be used for the actionable approvals, which is why I was trying to use a user's mailbox that is shared via delegate permissions as this seems the only supported way, but alas we get "Failed to validate the signature of the actionable message card."

     

    I asked CoPilot about the approvals and it firmly stated having "Full Access" was sufficient to make approvals on behalf of another user account. 

     

    If you did find a solution, I would appreciate hearing it!

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