A DNS error, the host server for the recipient domain name cannot be found
Causes
- Normally due to misspelling of the domain name part of a recipient email address.
- If email address is correct, then it may be due to your mail server network configuration or conf
Fixes
Step 1: Incorrect Domain Names
Check all the recipient email address for incorrect domain names.
Step 2: Verify DNS Records
Verify DNS records for the domain with tools such as IntoDNS or MXToolBox.