The account or domain may not exist, they may be blacklisted, or missing the proper dns entries. (DNS Entries)

Symptoms

When sending mail to a domain on your server, the message fails with the following error:

user@domain.tld is undeliverable: The mail server could not deliver mail to user@domain.tld. The account or domain may not exist, they may be blacklisted, or missing the proper dns entries.

Description

This issue will occur if the domain is not configured with the correct DNS records. MX records must be properly defined to point to the server that hosts email.

Workaround

Verify with your DNS Host that your MX records are pointed properly. If the cPanel server is your DNS host, you can see the records in the DNS Zone Manager:

How to edit a DNS record in the DNS Zone Manager

An MX record must point to a fully qualified domain name (FQDN) and will look something like this:

domain.tld. 3359 IN MX 10 mail.domain.tld.

If the issue persists, make sure that the correct mail routing settings are selected:

The account or domain may not exist, they may be blacklisted, or missing the proper dns entries. (Mail Routing)

Additional Information

How to create an MX record in cPanel