Set-MailboxMessageConfiguration Not Applying in Outlook Web – Anyone Faced This?

Question

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Hi Community,

I'm trying to apply a custom HTML signature using PowerShell via Set-MailboxMessageConfiguration, specifically targeting Outlook Web (OWA) in Exchange Online.

Here’s what I’ve done so far:

• Enabled the signature options using:

    powershellCopyEditSet-MailboxMessageConfiguration -Identity "******@domain.com" -AutoAddSignature $true -AutoAddSignatureOnReply $true
  

• Verified that OWA settings allow HTML signatures.
• Tried multiple sessions and browser refreshes – still not reflecting.

I also enabled the "Postpone command" functionality but no luck yet. The Set-MailboxMessageConfiguration cmdlet executes successfully with no errors, but changes don’t appear on the client side.

Has anyone successfully managed to push HTML signatures to OWA via PowerShell in Exchange Online recently? Is there something I’m missing or a delay in backend application?

Any help or insights would be greatly appreciated. 🙏
Thanks in advance!

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Answer 1

I have the same issue. I am running the following powershell script and then go to New Outlook. No signatures are added in Outlook.

I have not tried in OWA as we do not use OWA. Anything that can work with New Outlook would be appreciated.

$mailbox = "*****@someemail.com" # The email address of the user*

$signatureHtmlBody = @"

Best regards,

FirstName LastName

Some Title

My Organization

0123 654 987

"@

$signatureName = "NewSignature" # The name of the signature

Set-MailboxMessageConfiguration -Identity $mailbox -SignatureHtmlBody $signatureHtmlBody -SignatureName $signatureName -DefaultSignature $true -AutoAddSignatureOnReply $true -UseDefaultSignatureOnMobile $true

Answer 2

Hi,

This is my second follow up regarding to your issue. We would like to know if the issue you have raised to us is still on going. If yes, please reply to the thread so we can continue troubleshooting your concern.

Thank you.

Regards,

Fordy B.

Microsoft Moderator

Answer 3

Hi,

We have noticed that you have not replied to our last response. We would like to know if the issue you have raised to us is still on-going. If yes, please reply to the thread so we can continue troubleshooting your concern.

Regards,

Fordy B.

Microsoft Moderator

Answer 4

Hello,

Welcome to the Microsoft Community Forum. Please accept our warmest regards and sincerest hope that all is well despite the situation you find yourself in.

I understand you're facing issues with applying a custom HTML signature in Outlook Web (OWA) using PowerShell's Set-MailboxMessageConfiguration in Exchange Online. Here are a few things to consider:

1. Changes made using Set-MailboxMessageConfiguration may take some time to reflect in OWA due to synchronization processes.
2. Ensure that the user's mailbox is properly licensed and has the necessary permissions to apply the signature.
3. Double-check the syntax of the PowerShell command to ensure it's correctly targeting the user's mailbox.
4. Consider clearing browser cache and cookies or trying a different browser to rule out any local caching issues.

Hope this helps.

Best Regards,

Fordy B.

Microsoft Community Moderator