Your domain is not yet pointing to our nameservers ns1.infinityfree.com and ns2.infinityfree.com. Please change your nameservers at your domain name provider and wait a few hours for the changes to take effect. You can also create an account with a subdomain first.
There appears to be an ongoing issue with the hosting platform which makes it impossible to create a new account at this time. I’ve reported to iFastNet, and in my experience issues like this are fixed within a few hours.