Originally Posted by GoldenBeaverHos
It would be a good idea to get a static IP address and then whitelist your IP address in CSF or any other firewall.
Just whitelisting IP is not the solution, OP needs to figure out the cause of the problem ,because if it's blocking you it then it must be even blocking your clients or site visitors, i think it's configuration issue with CSF or cPanel.
From my experience there are few possible causes:
1) may be some mail client is connecting too often or making multiple connections to imap/pop3 and probably the connection times out, sometimes if there are too many simultaneous connections to same imap account, the imap server starts accepting passwords for new connection and it might trigger csf to consider it as a brute force and might block your IP
2) if you have some process that's trying to access some website on your server, then possible some mod_security rule is causing it
I hope it helps