Also, make sure to appeal here: https://appeal.cubecraft.net and if your appeal gets denied and you believe it's a false ban then please contact the staff member who punished you.Hello, you can know more about blocked connections here: https://help.cubecraft.net/en/article/blocked-connections-aod7sq/
If your blocked connection starts with "C", you'll have to wait until your ban expires. It can take from hours to months. So, I would recommend you to be patient.
That happens because someone was hacking on your IP, that's why you got banned.