ManageWP Backup Issue with Cloudflare

May I ask, does the request show any error like “504 timeout”?
Was the request/script running longer than 100 seconds?
Or any other error shown maybe in a Firewall events, if being blocked?

May I ask have you added the IP address(es) to a IP Access Rules, if so, did you selected “Allow” or “Bypass”?, otherwise maybe you added it into a Firewall Rule with the action “Bypass”?