I checked crazy-about-it.infinityfreeapp.com and it seems to be working “fine”. It redirecting to a spam site for me, but that’s caused by the PHP redirect you uploaded. The hosting service itself is working. Are you still having trouble with this subdomain?
The other domain is your main domain. That’s just an internal identifier, it doesn’t actually do anything, and you cannot view your website on it. So seeing errors when trying to access the main domain is normal, and doesn’t say anything about your actual website.