You need to make sure you have configured the DNS correctly. Usually these automation tools like WHMCS and also WHM, configures many basic DNS entries automatically and hence you maybe not aware of how DNS works exactly.
Internet is accessible only via IP address. As IP address are numerical figures, its hard to remember them. Hence we have domain names but these domain names are pointed to IP address itself as internet works in the IP segment itself.
Binding a domain address to an IP is what DNS do.
So if you have added a nameserver entry, you must add A record of nameserver entry with the server IP to make the nameserver work.
You can private message me with your domain details and I will check what exactly went wrong with your configuration.
you are right, WHM automatically create A record for NS and point it to server IP and in CyberPanel we have to do it manually and this is the mistake I’ve done.