Why I can not use ssl full(strip)model

Website, Application, Performance Security
3

Please make sure your webserver/VPS is answering requests on port 443.

In Full & Full (Strict) mode Cloudflare sends requests encrypted to the origin to port 443, not to port 80 anymore. Just make sure your webserver will answer these requests and also responds with a valid SSL cert.

But generally speaking, error 521 means “Web server is down”.

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