Could you please help me?

[fritex]

May I ask which steps have you tried for troubleshooting 521 error from the article below so far?

Community Tip - Fixing Error 521: Web server is down

Error Try the suggestions in this Community Tip to help you fix Error 521: Web server is down. Background A 521 error happens when we are unable to make a TCP connection to your origin server. Specifically, Cloudflare tried to connect to your origin server on port 80 or 443, but received a connection refused error. This is often caused by security or firewall software and happens if the origin server has directly refused Cloudflare’s proxy request. [Banner in tip catalog] Quick Fix Ideas …

What port do you use on your origin host/server for your web application?

Before moving to Cloudflare, was your Website working over HTTPS connection?

May I ask what SSL option have you got selected under the SSL/TLS tab at Cloudflare dashboard for your domain ( Flexible, Full, Full Strict … )?

Kindly re-check if Cloudflare is allowed (firewall, etc.) to connect to your origin host to as follows in the below article:

• https://support.cloudflare.com/hc/en-us/articles/201897700-Allowing-Cloudflare-IP-addresses

Nevertheless, Cloudflare IP addresses list can be found here:

• IP Ranges