Unable to send and receive email after domain name change

[ctgraham]

The difference between the SMTP username and the From address is a question of SPF and DMARC. There are a number of threads on this board which describe this, the most recent of which is here:

OJS 3.1.1 and DMARC?

Here is my current understanding: DMARC is a framework which describes to the recipient Mail Transit Authority (MTA) how to deal with violations of DKIM and SPF. DKIM digitally signs a message to declare authorship. That is, validating that the SMTP headers are accurate for the actual sender. SPF publishes for a domain what hosts are allowed to send mail “from” the domain. This is muddied by distinctions between the MAIL FROM (envelope sender), the SMTP From, SMTP Sender, and SMTP Return-Pat…