Every time you register domain name with Namecheap or any other registrar...
you have to go back to the domain manager and edit the DNS settings to point to
your own hosting account...
I just discovered today that in Namecheap you can set Checkout Settings in your profile where you can list your default DNS servers for your every new domain registered..
so that this step of manually changing the DNS from Namecheap to your own server is
It is here to do exactly:
Login to your Namecheap account > My Account > Manage Profile > Checkout Settings
Or after logging into your account simply access this URL..
Hope this saves you some time in future with new domain registrations.