Outbound email that is scanned goes into QUEUE and then goes to FAILED

I just upgraded my XG firewall from v17 to v18.  Previously everything was working great.

I have had a number of issues I have been trying to solve.

This next issue deals with outbound email.

When I send an outbound email it hits a firewall rule that has the email scanned. 

When this happens the email goes into the MAIL QUEUE.  It sits there and then goes to FAILED.

How do I diagnose what is going on?

If I uncheck the SCAN EMAIL in the firewall rule the email sends with no problems.

Any help would be appreciated.

Thank you,

Peter Geremia