Salesforce put a random tracking string of the "domain" when sending emails on your company's behalf.   If you want to Whitelist salesforce message, you will need to add the following to Filter Rules > Pattern Filtering > Whitelisted Patterns:


/(From|Return\-Path|To):\s+.+\@.+\.bnc\.salesforce\.com>?\b/


A typical email address from Salesforce.com might look something like this, but the string of the email domain changes from message to message:

faizal=spamtitan.com.com__0-86skyqc89gc8ra@lsfy4puwmrpv1u.3-jhlxeam.na13.bnc.salesforce.com


The:  \@.+ is used to match everything in red