What error do you get? Can you share a screenshot of it?
May I ask when you navigate to the Firewall tab → Overview to check for recent firewall events, is your IP being blocked or rather the IP of the origin host/server?
Regarding the Firewall Rule, is it the 1st from above on the list of the Firewall rules? (priority order)
If it’s your origin host/server IP being blocked/challenged, I’d suggest you to add your origin host/server IP to the Firewall → Tools → IP Access Rules with the action “allow”.
Furthermore, if it’s your own IP, may I ask if you are using some VPN connection, or a Tor Web browser, or using some kind of a web browser extension (adblock, privacy, antivirus)?