What you see when your domain has this problem
Unable to resolve DNS Details area Ignore

More Information About Domain Dns Failure

This is a critical error. The Domain Health report performs initial DNS queries in order to build a collection of servers to perform tests on. If the tool encounters an error while performing these initial DNS queries, you will see this DNS Failure error. Additional information will be contained in the transcript.

Possible types of problems that could cause this are DNS server failure, misconfiguration, or bad or missing data at the root srevers from your registrar.