Auto SSL can take up to 24 hours to take effect, so you might just have to give it some time. As for your main domain, it seems to work fine. You might need to clear your cache, or the contents of the domain's "public_html" folder.
The .heliohost.us subdomains don't require registration on a registrar at all. You just specify one when you sign up and you get it automatically.
If you have a different domain on your account already and want to change it to one of our free subdomains, let us know and we can make that happen