I see you are getting a 521 error, below are troubleshooting steps for the error
Error 521: web server is down
Error 521 occurs when the origin web server refuses connections from Cloudflare. Security solutions at your origin may block legitimate connections from certain Cloudflare IP addresses.
The two most common causes of 521 errors are:
- Offlined origin web server application
- Blocked Cloudflare requests
Resolution
Contact your site administrator or hosting provider to eliminate these common causes:
- Ensure your origin web server is responsive
- Review origin web server error logs to identify web server application crashes or outages.
- Confirm Cloudflare IP addresses are not blocked or rate limited
- Allow all Cloudflare IP ranges in your origin web server’s firewall or other security software
- Confirm that — if you have your SSL/TLS mode set to Full or Full (Strict ) — you have installed a Cloudflare Origin Certificate
- Find additional troubleshooting information on the Cloudflare Community.