It might be a iptables firewall on the forum server or an inbuilt firewall in the vbulletin application that has your home IP blocked due to too many failed login attempts or something.
Is your home connection a static IP? If not sure, quick test it by going to
http://whatismyip.com - make a note of the IP it reports back. Then pull the power from the router - wait a few minutes then power back up and check your IP again - if it's the same IP as previously then it's quite likely to be static and a firewall on the forum server side might be blocking you. You should then contact support or a forum mod to pass on your IP to get it checked and if found removed from any IP blacklist.
Another test - you could use a proxy server to access the forum from home EG
https://www.proxysite.com/ - if you get the forum.fractalaudio.com site to load using a US proxy server then it's further evidence that your home IP is probably blacklisted.
Cliff mentioned a day or 2 ago that the current server hosting the forum is struggling - so all sorts of weirdness can be expected until they get the planned upgrade done in the near future.