Greetings,
Thank you for asking.
I’d suggest to navigate to the Cloudflare dashboard, therefrom follow the tab Security → WAF → Tools → IP Access Rules and add your origin host/server IP address there with the action “allow” for your Website.
Helpful article:
More about this service here:
May I ask which Cloudflare plan type are you using? 
Also an option too. Once process finished, switch back to 
.
I’ve had to use it for “live” WordPress Website migration and few similar cases, because the process would throw the default 524 “timeout” error.