Blocking Constant Contact emails

On 11/17, Cox blocked the delivery of emails from my Constant Contact account sent to @cox.net addresses. Successful delivery to the same addresses happened a just a few days before.

The Constant Contact Delivery Support team informed me that I needed to authenticate CC emails sent using my domain, by adding two CNAME records to my domain's DNS:

ctct1._domainkey.<mydomain>.com
100._domainkey.dkim1.ccsend.com

ctct2._domainkey.<mydomain>.com
200._domainkey.dkim2.ccsend.com

If you're having similar problems, look at "Self-authenticate your email address" under your Constant Contact My Account -> Advanced Settings for guidance. Because DNS propagation can take up to 48 hours, Cox has prevented me from reaching my subscribers until the fix I apply compensates for their failure.

  • Cox Mail system prevents mail systems that do not adhere to proper DNS requirements, from sending mail to their subscribers. many SPAMMERS will simply try to setup a mail server with minimal DNS and try to send out thousands of spam emails, and Cox's system of requiring proper DNS prevents it.