R=fail_remote_domains: The mail server could not deliver mail to

When trying to send emails from the server, you receive a bounce back as below.
R=fail_remote_domains: The mail server could not deliver mail to. The account or domain may not exist, they may be blacklisted, or missing the proper dns entries.

Even though the server IP OR domain isn’t blacklisted, bounce back shows it to be blacklisted.

Workaround is to change the resolvers and set them as below.
nameserver 8.8.8.8
nameserver 4.4.4.4
It’s time to try sending emails now. Emails will be delivered properly.
Read more: Know How to Set a PHP Redirect