new exchange server not triggering rules

We use the web messenger with key words in the subject to trigger the PGP rules. and to a lesser extent content in the message itself can trigger the PGP rules.

I am trying to migrate to a new exchange server, but when I change the routing of internet bound messages, the rules do not get trigger under any condition. the message gets sent directly to the recipient. the message should be stopped at the PGP Web Mail Protection server, and a notification should be sent.

the messages are delivered to most domains (gmail, outlook.com, comcast.net) but are rejected by AOL.

apparently there is something about the message format I have not configured, that is configured on the old server.

what have I missed? Thanks in advance.