Issues with hostname and domain

[mattander2022]

So I recently purchased a dedicated server, installed cPanel on it to learn about server administration as I have recently became a student for IT and I thought that diving head first into creating a web hosting platform would help me gain valuable experience.
With that said I attempted to change the hostname of my cPanel as it was still using the cpRapid host name, and when I changed it, it posts the cPanel web page saying there is something wrong, some type of server misconfiguration. I have not dared to exit out of my WHM panel from the cpRapid domain as I am unable to access my cPanel or WHM through the domain that I registered and configured for the cPanel/WHM.
I added the A Entry for the hostname. On my domain registrar (Namecheap), I have the Advanced DNS settings pointed towards my main server IP address, so I don't see what the problem is and why I am unable to access my cPanel/WHM directly through my domain. Any help? Links for a comprehensive guide? Any help is greatly appreciated.

 

[cPRex]

Hey there! You can always access WHM through the IP address of the server in case there is an issue with the hostname, so no worries about not exiting.

In general, it should be as easy as changing the hostname to what you want through WHM and ensuring the A record is in place. What is the exact error message you received?