AAronr, I have several VPNs, 4 at the moment, IPVanish is one of them, Astrill and a couple others too. I use them for viewing Hulu/Netflix in different regions. Some servers on all 4 companies are blocked by HTC, I suspect it's due to somebody using a VPN to regain access to the forum after being banned, and causing havoc, and then that IP being banned. Certain servers from all over the world, if I forget I have the VPN on and log into HTC, I get that same message, then I have to go in and remove that cookie manually which auto bans my account. Skuzzy helped me figure all this out months ago, I had the exact same issues as you.
I understand completely why HTC deals with VPNs as they do, again, many have used them for nefarious purposes here, and I try to ensure I have mine off before opening my web browser.