Is disabling IPv6 an option here? A prior poster suggested as such, but I don't know if that was just a general suggestion or if that's actually possible in O365 settings.
But if you can .... yes, try sending outbound mail only via IPv4. A "well known secret" is that Gmail filters mail from IPv6 connections more harshly than IPv4. Maybe less than they once did, and certainly you could question if it's fair or not, but I saw clear evidence of it in the past. I personally have IPv6 disabled on my MTA because of it. Also make sure your DKIM is set up as YOU and not just as the default *.onmicrosoft.com that Microsoft sticks on there for those who aren't fully configured. If you want folks to look at headers and offer up additional suggestions, run a test using https://aboutmy.email and share the results link here. I'll take a look and advise, and I imagine others will, too. Cheers, Al Iverson -- Al Iverson // 312-725-0130 // Chicago http://www.spamresource.com // Deliverability http://www.aliverson.com // All about me https://xnnd.com/calendar // Book my calendar _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
