This is a default setting of cpanel. If the user tries to login into the cpanel or his webmail and he does approximately 3 mistakes in a few minutes, the server automatically bans its IP. Of course, there might be differences between the providers.
If your IP is static, then you can just restart your router in order to get a new IP. Otherwise, you will have to get in touch with your web hosting provider in order to get your IP removed from the ban list.