IIS and Cloudflare, getting Website is down error

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Hi, I’m getting Website is down error only when SSL security is set to Full (strict). I have Cloudflare Origin CA installed on the server.

This is the added certificate in IIS server certificates:

What is the domain name?
darkcat.cloud

Have you searched for an answer?
I’ve investigated myself and couldn’t fix the error.

Describe the issue you are having:
Can’t navigate to the website when SSL security mode is set to Full (strict) since website is going down.

What error message or number are you receiving?
421

Was the site working with SSL prior to adding it to Cloudflare?
Yes, if the SSL security mode is lower than Full (strict) it works.

Have you tried from another browser and/or incognito mode?
Yes

Certificate is also set in IIS domain bindings
image

I would check the IIS settings on the server. Maybe something is not setup correctly with SSL.

I double-checked the settings, re-added the certificate and error remains

UPD: I’ve paused Cloudflare on the domain and and google gives the following error:

If you are getting this error when not going through Cloudflare, then there is something misconfigured on your origin, and you’ll probably get better answers on something like serverfault

1 Like

Recreated CSR again, will try to create new certificate

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