I have had a similar problem there forever; my internet provider's IP must be listed there as unwanted. I have to use VPN to get there. My account isn't banned, but if I connect with my regular IP, I see a similar message (although nothing about my e-mail or "Stop Forum Spam & Cleantalk.org"), then I have to delete my cookies for this site, otherwise I won't be able to sign in even with VPN. I'd say they are a bit overprotective.