“Nameserver [ns1.domain-name.com] doesn’t exist at the registry”
When you are configuring a domain name with custom name servers they need to be registered. It’s free and has to be done with the registrar of the domain name. To discover your registrar use this web site www.who.is and type in your domain name then look at the registrar entry. If you are a reseller with Tucows or your hosting provider is ask them to do the following.
1. Login to their reseller control panel and locate the option to “Add Nameserver to All Foreign Registries”.
2. Type in the custom name server address and click on add nameserver.
You will need to wait a few hours for the addition to propagate before you can change the name servers on your domain name. I usually just wait a day.