You have completed the server-side setup for Exclaimer Cloud - Signatures for Microsoft 365. You have configured a Data Loss Prevention policy that blocks certain email content but allows users to override the Data Loss Prevention policy.
When a user sends an email that conflicts with a Data Loss Prevention policy but chooses to manually override the policy, the email is still blocked by the Data Loss Prevention policy.
Due to the email being routed over a connector, the Data Loss Prevention override information is lost and the email is blocked once it returns from Exclaimer Cloud. This issue would also occur with any other email add-on service using this mail flow model.
For any users that need to override Data Loss Prevention policies, it's possible to use client-side rules to apply signatures instead of server-side rules.
For more information, see how you can enable a client-side signature.
It is necessary to bypass the Exclaimer Cloud servers for these messages. This can be done in any one of the following ways:
Automatically bypass specific users from the Exclaimer Cloud servers.
To do this, add the sender address to the exceptions (the sender address matches) in the mail flow rule. For more information, see How to exclude a message from having a signature applied: steps on how to create an exception for a given domain.
Manually bypass messages from routing to the Exclaimer Cloud servers.
To do this, use a subject line or message body exception. For more information, see How to exclude a message from having a signature applied: steps on how to create an exception for specific keywords or phrases.