If you are using a reseller, report the FP to your reseller and they will report it to ST. If you are a direct customer of ST without a reseller, you would need to contact sales@smartertools.com or open a support ticket with them and submit the FP. Either way, you would need to submit the following info:
 
Provide a copy of the original .EML file, along with the rule that was triggered. This information can be found
in the Message Sniffer logs, and would reference the .EML file name.

Example:
<i u='20180320162359' context='--INITIALIZING--' code='0' text='Success'/>
<s u='20180320162359' m='c:\SmarterMail\Spool\SubSpool1\341445313016.eml'
s='0' r='0'>
<p s='12' t='15' l='428' d='180'/>
<g o='0' i='10.1.9.75' t='u' c='0' p='0' r='New'/>
</s>