For any critical email delivery make sure you can address this thing with the mailsender of choise: 1)SPF, 2)DKIM, 3)DMARC [2] (DMARC is often forgotten or c

For any critical email delivery make sure you can address this thing with the mailsender of choise: 1)SPF, 2)DKIM, 3)DMARC [2] (DMARC is often forgotten or can be super noisy when set up. Postmarc offers a aggregation service for free that sends you a weekly summary), 4)Dedicated IP 5)Reverse IP look up [1] (locate a dns PTR record for that IP address) should match the sender. Not everyone supports 5). 4 and 5 is what you end up paying for, but totally worth it. Sendgrid, SES, Mailgun etc. [1] https://www.mailgun.com/blog/deliverability/reverse-dns-white-labeling-hello-my-name-is/#chapter-1 https://www.mailgun.com/blog/deliverability/reverse-dns-whit... [2] https://dmarc.postmarkapp.com/ https://dmarc.postmarkapp.com/