And that rule is probably designed to hit legitimate sendgrid emails. They have become a hacker and spammer haven over the last year and a half approximately.
On Thu, May 20, 2021, 16:49 Alan Hodgson <ahodg...@lists.simkin.ca> wrote: > On Thu, 2021-05-20 at 16:12 -0400, Alex wrote: > > > X-Envelope-From: > <bounces+3940809-b10a-43194=hotel.example....@em8909.cookspest.com > > > > > Perhaps it's because Return-Path is null? > Return-Path: <> > > > Return-Path is supposed to be where your MTA stores the envelope sender. > That it doesn't match is probably a problem. > > > And yes, SPF falls back to testing the HELO host if the envelope sender is > empty (which should only occur in bounces or auto-responses). >
