Personalized Domain Name!

I'm having a slight problem using this feature.
When I type my website url in there , it gives me this message: The supplied domain name is not well configured.

Then it gives me like a paragraph talking about DNS administrator and CNAME and all of that. I don't understand any of it. So could someone please help me? I was going to post this in other problems but my past 2 questions haven't got answered by staff (other members helped me). And this does sorta have to do with my admin panel!

THANKS!

Can you please provide the url please?

thanks

This is my website. http://www.awlonlineweb.com

It seems you didn't buy your domain name here, the issue should be checked by your registrar.

Oh, so that's the problem. I thought you could use any domain you owned. I didn't know you had to buy it from here!