Intermittent 404s directly from Cloudflare

Our site, just today after many months of proxying through Cloudflare, began responding with 404s for everything including our static home page. We were getting > 50% 404s from Cloudflare, but they weren’t coming from our servers.

I tried purging the cache, but that didn’t do anything. The only thing that worked was turning off the DNS proxy. Has any else seen problems like this?

One other comment: the 404 returned from Cloudflare had no content.

We were getting > 50% 404s from Cloudflare, but they weren’t coming from our servers.

Cloudflare doesn’t generate 404 errors. Do you perhaps have Page Rules enabled that might be modifying the request before it reaches your server?

https://support.cloudflare.com/hc/en-us/articles/115003014512-4xx-Client-Error

I wish it was that simple. We don’t have any Page Rules that pertain to our home page. When I curl’d the site, I only got a 404 status code; no body data was returned.

What were the response headers?

* TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
* TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
* old SSL session ID is stale, removing
* Connection state changed (MAX_CONCURRENT_STREAMS == 256)!
< HTTP/2 404 
< date: Tue, 19 Jul 2022 04:42:30 GMT
< content-type: text/html
< access-control-allow-headers: *
< access-control-allow-methods: *
< access-control-allow-origin: *
< cache-control: private
< p3p: CP = " IDC DSP COR ADM Devi Taii PSA PSD Ivaí IVDi CONi HIS OUR IND CNT "
< x-aspnet-version: 4.0.30319
< x-powered-by: ASP.NET
< x-xss-protection: 0
< cf-cache-status: DYNAMIC
< expect-ct: max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"
< report-to: {"endpoints":[{"url":"https:\/\/a.nel.cloudflare.com\/report\/v3?s=oDhSDV6PyzNRaVtFfhp3gcDFbPz4%2BqzMVBMraLuod8WYX76F5xlRzJSvx4T%2BJ7pKs8YlHmyuTA1XDnv7680e7WYWvBGJeQvb0KyzsUmKFGzloeDXQUuzIPtVVdfj%2F5vX90%2Fa2B%2FY"}],"group":"cf-nel","max_age":604800}
< nel: {"success_fraction":0,"report_to":"cf-nel","max_age":604800}
< server: cloudflare
< cf-ray: 72d0ca75df1ae472-SEA
< alt-svc: h3=":443"; ma=86400, h3-29=":443"; ma=86400

This response was generated by the origin.

2 Likes

Thank you for pointing that out. I missed that.

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