Hosting Knowledge Base
How to get WWW on a subdomain?
The WWW prefix for subdomains (also known as fourth level domains) is not supported on our shared hosting environment due to security reasons. You can, however, access your subdomains without the WWW prefix like http://subdomain.domain.tld .
The WWW prefix is automatically added and made available to all hosted domains, so if you host the domain yourdomain.com into your account, the subdomain www.yourdomain.com will be added automatically for you.