Hello,
When testing your site, both the www and the non-www are working for me. Did you already fix the issue?
For those that may have the same question, simply be sure to point the www record to your domain name. For example, if your domain name is example.com, the main record will point to an IP address, like 123.456.789. Make sure the www record literally points to 'example.com'.
This is done for domains registered with us by default, but for domains that are registered with another registrar, it may need to be done manually.
Kindest Regards,
Scott M