Custom Nameserver Restriction for .com, .net, and .edu Domain Names
Domain name extensions .com, .net, and .edu have a special restriction when using custom nameservers (see Registering Your Own Nameservers/Hosts for information on registering custom nameservers.) This is a restriction by their registry, VeriSign®.
The restriction prevents circular nameserver references from resolving properly to the hosted website.
What is a circular nameserver reference? — If you create custom nameservers for two domain names, a .com and a .net, for example, and the domain names use each other's nameservers, the reference is circular.
Example of a circular nameserver reference:
coolexample.com uses: ns1.coolexample.net and ns2.coolexample.net
coolexample.net uses: ns1.coolexample.com and ns2.coolexample.com
Here's the fix: Change the nameservers for one of the domain names.