We are receiving newsletters masking as our own domain which we are allowing via SPF. We use Barracuda for the primary filter and also added IP allow. Some are going to the Junk Mail folder so we added the IP in the Anti Spam Policy - Connection Filter in office 365. All is good except for one particular email. We don't want to add the specific email to be allowed as we don't want it to be spoofed.
All the headers are the same (including the sending IP). How do you determine what's still causing that specific email to go to the Junk Mail folder?