Coinloaf shows a directory listing, which means it is correctly set up, but there are no files. Remember that new domains can take time to set up and work.
The Directory Listing means your domain and account are all set up, but there are no files in the directory of your website. Note that if you add a domain as an Addon Domain, a new directory will be created for the domain so you can upload a new website to it.
If you want to move an existing website over to the Addon Domain, you’ll need to move the files from the directory of the old domain to the directory of the new domain.