After installing Comodo Firewall with DNS, I get msg email to Earthlink blocked

After installing the Comodo Firewall, I get a message from earthlink that my mail server has been blocked from sending mail to earthlink. It says something about mail server dynamic DNS being a possible cause.

Should I not use Comodo DNS servers? How do I change that choice and not use them after the program has been installed?

Uninstalling does not remove the Windows setting to revert to your old DNS servers. Go to Free Comodo Secure DNS | Best DNS Security Solution 2022 and look in the right bottom corner and click on the link for your OS.

Follow the tutorial but at the end set to automatically obtain DNS servers.