Domain Name not pointing correctly!

I am fairly new to this stuff so please go easy on me! not too technical!
I have set up 2 blog sites using wordpress, in both cases I have tried to point a domain name I own directly to the blog.
when you try typing in the domain name you get an error but the site apears to work fine if you dont use the domain name, what am I doing wrong?
for an example, one of the domans is located at: https://yz5059380.ehost-services144.com/drc/ i.e. in the sub folder ‘drc’ when you go to the site via the above web address or via the domain name associated with the parent folder (www.cavanagh.cc/drc) you get to the wordpress site correctly, but using the domain name https://www.cavanagh.me just throws up an error, this domain name is on the same account and the domain name is pointed to the drc sub folder.