HTTP 200 from origin, 520 from cloudflare

I run I confirmed both www and @ DNS records were resolving before enabling proxy on only my www subdomain. I use let’s encrypt and have strict SSL enabled

Navigating to gives me an HTTP 200, but Cloudflare gives me a http 520.

{redacted} - - [22/Feb/2022:05:34:17 +0000] “GET / HTTP/1.1” 200 20386 “-” “Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:97.0) Gecko/20100101 Firefox/97.0” “”

Running the curl command suggested in the documentation returns valid headers and my website HTML if I take out the -svo options.

curl -svo /dev/null --connect-to ::{redacted}

I’m really at a loss here why Cloudflare cannot work with my website.

I solved this and posted my fix on stack overflow. I added a content security policy in my nginx server block and it included a line break that Cloudflare did not like. Check your added headers and try disabling and adding them back one by one to see if that’s the issue.

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