After add on domain

So I did add on domain everything was working. A few hours go by both websites go down saying website coming soon. The new website is showing back up but the main domain is still down. I think I linked these two sites and shouldnt have. There is a subdomain showing both websites in the .com I think I need to delete some stuff and possibly delete and add the domain again. Im not sure I should do that because it might make it worse. I am new at this. Any advice because I think I will try it. Thanks