Step 1: After enabling Firewall, click on the arrow to the bottom-right of the Firewall card.

Step 2: Click on Blocked IPs button on the bottom-right corner of the Security section.

Step 3Here you can see the list of IPs that are blocked from entering or sending requests to the website.

Step 4: Select the IPs you want to unblock on this list.

Step 5: Click the Unblock IPs  button.

Read more: How can I see the IPs Blocked from entering my website?