Hello I'm new to cPanel so pardon my n00bishness when it comes to it...

On one of my accounts I would like to make a subdomain so I set it all up in the manager just fine and it made the folder in my home directory but when I try to access subdomain.domain.com I receive an "Error 400 - Bad Request" message. Someone told me it may be a DNS Nameserver misconfiguration but I really don't know what to do. Any ideas?

Thanks for your time.