Both are working for me. Seems like some ISPs have incorrect information for the A records. Not sure if hosting has ever changed for the site, but I would go into DNS settings and check to make sure that halowheelmen.com and http://www.halowheelmen.com
both only have 1 A record listed, and that it's pointing to the right IP.
I just had this issue with Minecraft server, sometimes it would work and sometimes it wouldn't. Turns out there were 2 IPs listed, because I neglected to delete the old A record for that subdomain.
Confirmed, looks like http://www.halowheelmen.com
has 2 A records listed, unless this has something to do with CloudFlare: