Make sure you check your Zombie Protection Settings to make sure that the Email Accounts you’re using to send outbound mail are listed in the Miscellaneous section for exemption.
This section is found under Anti-Virus Techniques / Outbound tab.
Also add the sending Email address to a Filter for Outbound email under Policy and Compliance / Filters. Setup the Filter so that mail FROM (email address) has the “Deliver and skip SPAM and Phishing analysis” Action, name it and save it. Make sure it’s enabled.