You need to host the website under www subdomain or create a host redirect that will allow you to open the website as you want it. You should better contact the host where the website is hosted, so they will be able to help you with the project hosting.
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items