Hello Jay, I'm sorry to hear you're having trouble with Content Filters. First, Trusted Senders are excluded from the vast majority of spam checks per our help documentation linked below, but will still be subjected to SPF/DKIM checks, and any Content Filter entries which are set up on the domain, as these are engaged after the spam check process. 

With that being said, if the sender fails SPF/DKIM checks (performed on all senders) this will then subject them to additional spam filters, opening the message up to further rejection for spam reasons. As such, the solution for these issues is two-fold:

1. First make sure that the sender is passing SPF/DKIM checks on receipt. This can be done by opening the raw content of a message received from the sender and checking the spam check header values. If you see these senders are failing SPF/DKIM checks I recommend investigating the Spam Checks logs in SmarterMail to determine the root cause. Please don't hesitate to submit a ticket with us if you need a hand!

2. Implement additional conditions on your domain-level Content Filter to prevent it being triggered on specific senders/sender domains. I've included an example below of a condition that should work in your case: 

This will allow the Content Filter to continue being applied without tagging your critical senders. This, combined with confirmation they are passing spam checks, should allow these messages to land in your inbox once more! I hope this helps!

Thank you for the workaround; that at least gets us over the initial hurdle.  That still brings up the nagging little detail that in the case of many Trusted Senders, the admin must enter that sender's email at least twice:  once as a Trusted Sender, and again as an exception to the Content Filter.

I'll propose a future enhancement:  Have a switch on the Trusted Senders tab to "Bypass Content Filters".  The customer we're working with has an extensive Content Filter, and large Trusted list.  They're a fairly large real estate brokerage, who has populated the Trusted Senders list with all the senders they absolutely cannot miss emails from.  They've been losing emails, and none of us were aware that "trusted" still didn't bypass the Content Filter.  

A switch would give that option to make Trusted actually really mean "trusted".  

All that would need happen is, before any Content Filter is applied in the mail flow, check to see if the bypass switch is enabled.  If so, skip filters.