SSL Full Option gives me Web server is down Error code 521

So i use Cloudflare and when i turn the ssl to flexible everything works fine but when i go to full it just loads the known error page by Cloudflare and says cant connect to host and on the screen its Error 521, so my question is how do i fix it, i think it might have a problem with my domain maybe? because its a .dev domain and i noticed on certbot that it only connected with a certificate and it wasnt possible to enter the domain through http so maybe thats a problem but how do i fix it?

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

Can you double-check if your web hosting provider issued an SSL certificate which is still a valid one for your domain(s)? :thinking:

Before doing anything at Cloudflare settings, you could determine if you have a valid SSL certificate installed at the origin host/server by your web hosting provider or your own VPS/dedicated server following the steps from below:

  1. Use the “Pause Cloudflare on Site” option from the Overview tab for your domain at .
  2. The link is in the lower right corner of that page.
  3. Give it five minutes to take effect.
  4. Check with your hosting provider / cPanel AutoSSL / / Certbot / Let’s Encrypt or some other and renew it accordingly.
  5. Make sure site is working as expected without any errors via HTTPS.
  6. Only then should you un-pause Cloudflare and double-check your SSL/TLS setting to make sure it’s Full (Strict).

Here is a way to re-check if you correctly setup the SSL for your domain with Cloudflare:

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Thank you very much! I changed to Cloudflare because i wanted and SSL because Certbot blocked my certificate requests because i did to much so then ill have to wait until i can generate a new one and activate my certificate and then i can just turn on Full strict when the SSL Certificate is on and everything works without any other settings?

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