Is it only my VPN or all VPN's denied access to Forum

I use Ipredator as my VPN and RV Net will not let it get on the forum. Is this only true for Ipredator or are all VPN's blocked? I am going back to turn on the VPN now and will check back tomorrow or the next day, or whenever.

I do not understand the reason behind denying access but would like to know if there is a rational reason or ???.