Question
Why doesn't my hostname resolve?
Answer
There are several reasons that a server's hostname may not resolve. The most common issues are the server using a hostname for an unregistered domain, the domain's authoritative nameservers not having an A record for the hostname, the domain's authoritative nameservers lacking GLUE records, or the domain's authoritative nameservers being unreachable on UDP port 53.
Additional resources
What is an effective hostname?
How to change the server's hostname from WHM
