FYI it could be something like ipv6 causing you to be seen as spam but I figured I'd share this tool (https://www.mail-tester.com/ https://www.mail-tester.com/)

FYI it could be something like ipv6 causing you to be seen as spam but I figured I'd share this tool (https://www.mail-tester.com/ https://www.mail-tester.com/) which I've used successfully many times to get into inboxes (particularly gmail) with custom mail servers.