If a user sends an email to a distribution group for approval, then no signature is applied to the email. But, if the user sending the email is an approver or the distribution group owner, then that user's signature is applied to the emails.
This issue occurs when the Exclaimer Cloud rule is configured to have a group membership requirement for emails that are sent to Exclaimer Cloud. In the case of the group membership requirement, the moderated email has a unique email address attached to it rather than the sender's original email address - this causes the email to not match the conditions of the Office 365 rule.
To resolve this issue, remove the group requirement condition but leave The sender is located condition to ensure that a signature is added to the distribution group emails.
Follow these steps to locate the transport rule and remove the group requirement condition:
- Sign in to the Exchange Online admin portal (https://admin.exchange.microsoft.com) as an Administrator.
The Exchange admin center is displayed.
- From the left-hand navigation menu, select Mail flow, then select Rules.
- Double-click the Identify messages to send to Exclaimer Cloud transport rule.
- Remove the condition The sender is a member of (highlighted below):