A signature is not applied to Out of Office emails or automatic replies - Microsoft 365 – Exclaimer Cloud Knowledge Base

Scenario

You have configured Exclaimer Cloud - Signatures for Microsoft 365, and you notice that signatures are not applied to Out of Office emails or automatic replies.

Reason

NOTE: An email message consists of headers and body content. When an email is transmitted, the whole thing (headers and body) is wrapped in an envelope. The envelope specifies who it is from (MAIL FROM:) and to whom it is being sent.

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

For Exclaimer Cloud to determine which user signature to apply, then deliver the email back to Microsoft 365, it is essential that the MAIL FROM: information is provided with the email. If automatic replies are sent to Exclaimer Cloud, they will fail, as it is not possible to determine the correct route back to Microsoft 365.

Resolution

As automatic replies are sent without a MAIL FROM: address, a mail flow rule is created in Exchange Online - this ensures that these emails are not routed to Exclaimer Cloud, thus preventing the issues mentioned above.

The mail flow rule is called Prevent Out of Office messages being sent to Exclaimer Cloud and is automatically created when you connect Exclaimer Cloud to Microsoft 365.

Example:

If the Prevent Out of Office messages being sent to Exclaimer Cloud rule is missing, then you can re-run the connector setup wizard to recreate this.

Workaround

You can manually copy-paste your signature at the end of the automatic reply message; however, please note that Outlook does not support full HTML content for automatic reply messages. It will not display images and other HTML content in your signature.

Example: