1: Log into the cPanel for your WHMCS installation (Assuming it’s a cPanel server).
2: Click on PhpMyAdmin under the Databases tab.
3: Select WHMCS’s database.
4 : Browse the table “tblbannedips.”
5 : Click on tblbannedips and search for the banned IP address.
6: Click the “Delete” button.
That’s it!!