In this age of ever-increasing SPAM messages, email providers are setting stronger safeguards. One of these is DMARC. In layman’s terms, it means the email address listed in the header of an email ought to match the send-from email address. When you use a free email provider like @hotmail, @gmail, @aol, or @yahoo those servers would look at a newsletter and see the send-from email being their server, but the headers would reference the newsletter provider. Those servers would then tell the receiving email server not deliver the email because the header and the send-from addresses don’t match. This means your newsletter would not be sent or be sent to very few individuals.
A domain email address stops this from happening because usually the DMARC policies on a domain-based email are a bit more fluid and would allow those emails to be sent. In addition, a website administrator can adjust the DMARC policies to make sure that newsletters get sent as well.
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