VPSes, VPNs, proxies and other IP hiding mechanisms are generally banned on geekhack. Not all such mechanisms are banned, but many such allocations have been repeat offenders as the source of spammers and other ne'er do wells. However, there is an issue with SMF wherein, if you login from a banned IP and then login from an unbanned IP, your browser will display a ban message. It turns out that SMF actually asks your browser to ban itself via a cookie. Silly? Yes. Effective? No. Spammers rarely use actual browsers, and definitely don't listen to that cookie. Real users do use actual browsers and unfortunately get hit by this dumb bug.
Hence, if you think you have been spuriously banned, please clear your cookies. If you have been spuriously banned, you will magically become unbanned! Yay!
