I realize this is an old thread - but I have been having these issues of late.
I tried clearing cookies etc - have this issue across browsers.
And then I realized - if I'm on VPN to my work network, I don't hit this issue.
If I am directly logged in from my home Wi-Fi, I get the "Banned" message - again, I am fairly sure I haven't done anything to deserve it!
If I login using WiFi tethering from my mobile data, again, no issues.
So it seems my home WiFi / internet IP address is being blocked by the rotoworld forums (rotoworld website has no issues, only the forums) - no idea why.
Any help regarding this would be great!