A signature is not applied to Out of Office emails or automatic replies

Scenario

You have configured Exclaimer and you notice that signatures are not applied to Out of Office emails or automatic replies.

Reason why automatic replies are not supported for Microsoft 365

When automatic replies are sent from Microsoft 365, the MAIL FROM: information is intentionally left blank by Microsoft Exchange. 

For Exclaimer to determine which user signature to apply and deliver the email back to Microsoft 365, it is essential for the email to include the MAIL FROM: information. If automatic replies are sent to Exclaimer, they will fail because it is not possible to determine the correct route back to Microsoft 365.

As automatic replies are sent without a MAIL FROM: address, a mail flow rule called Prevent Out of Office messages being sent to Exclaimer is automatically created when you connect Exclaimer to Microsoft 365. This prevents the aforementioned issues. However, it can be possible for this rule to be missing.


_{The Exchange admin center shows which rules are present and enabled.}

Workaround

We recommend the following workaround to apply a signature to the Out of Office or automatic replies:

1. Copy your signature manually at the end of the automatic reply message.
   
   NOTE: Outlook does not support full HTML content for automatic reply messages. It will not display images and other HTML content in your signature.
   
   
   _{Your signature can be copied and pasted into the automatic reply template.}