Fix Mailgun “550 Sender has no A, AAAA, or MX DNS records.”
Updated 21 May 2020. Sometimes, we setup Mailgun for transactional email, because this helps web based forms, and other, email to get sent to the right place. Its also free, as in beer, at least for the first 10,000 mails a months. But we ran into a deliverability issue on one or two domains, which …