I have tested this plugin the client bought from here for his OCwebsite, its all updated to last version ( just to note ). But .... after setting it up, tried to login with my test user profile and the darn thing banned my IP. I checked my IP for any case in StopForumSpam.com but all clear there. Since there is no unbaning / whitelist I stopped the plugin. Please update/fix the plugin.

You may find ban reason in Users > Ban rules

My IP was not there, but there was user blocked with similar with MY IP  ( again from Bulgaria, was a real user ), last numbers ware difference, so I turned off the function for masked IP's