Seeking Help: Website Unreachable with CDN Proxy - Error 521

Website, Application, Performance DNS & Network
1

What is the name of the domain?

navidrome.ishell.stream

What is the error number?

521

What is the issue you’re encountering

When I enable the CDN proxy for my domain, my website becomes inaccessible.

What steps have you taken to resolve the issue?

Verified that the server is running and accessible when the CDN is disabled.
Checked the server logs for any request entries, but found none during the CDN proxy usage.
Ensured that the server already disable firewall

What feature, service or problem is this related to?

I don’t know

What are the steps to reproduce the issue?

enable the CDN

2

Can you disable the proxy for a moment?

Also, which SSL mode are you using in Cloudflare?

3

Thanks for the reply.
I have the CDN feature turned off now and I can access it normally

4

It looks like there is no DNS record for navidrome.ishell.stream now.

5

I’m not using cloudflare SSL, I requested the certificate from let’s encrypt alone

6

I’ve been able to get the address of the domain correctly on my end, maybe you need to wait on your end, or try clearing the dns cache.

7

Are you sure the domain in your opening post is correct? Because there definitely are no DNS records for that domain.

When you enable Cloudflare proxy/CDN, you also use their SSL. Which setting are you using there?

8

Yes, the domain is correct, could it be because it’s ipv6 only?

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I’m not sure I have cloudflare ssl configured, can you tell me where to check, I don’t see it in the DNS configuration.

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9

oops, my bad. I usually also check IPv6, but I forgot this time.

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10

::
Flexible mode

11

That’s why it doesn’t work with the proxy enabled. Switch that to Full (strict).

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12

Ok, I’ll try switching to Full mode, thanks.

13

You should not use Full.

14

Yes I switched to Full and then turned on the proxy and it works fine, thanks!

15

You should really, really not use Full. Only Full (strict) should be used.

1 Like
16

Yes, my description is wrong, I switched to Full (strict) mode. :rofl:

1 Like
17

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