Alt-svc Header Missing

I’ve noticed over the past week or two that Cloudflare sites have entirely stopped loading in HTTP/3 for me at all. So I decided to dig in and I noticed that there was no longer an alt-svc header in the page requests.

These are the response headers being sent on Cloudflare’s own website. So their own website, which is meant to have HTTP/3 enabled, doesn’t have it enabled. This happens to me on multiple devices.

Does anyone else see this on the Cloudflare network? It’s multiple domains for me that no longer include an alt-svc header.

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That does seem broken for me too. Have you opened a ticket? If so/when, please post the ticket # here.

To contact Cloudflare Customer Support, login & go to and select get more help. If you receive an automatic response that does not help you, please reply and indicate you need more help.

I don’t see the Alt-Svc header either, but my browser can still use HTTP/3 on sites where it’s cached.

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Just made a ticket, #2015531. Glad I’m not the only one seeing this weird bizarre behavior.

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maybe @LucasPardue might know? :slight_smile:

Hi i also have this issue and http3 protocol not granted… so please if have an answer instead of open 1000 tickets can you share here? thanks

Great question and very astute observation! We’ve had to disable HTTP/3 on a set of zones temporarily while we investigate an issue that was causing degraded performance in some cases. As soon as that issue has been resolved we will re-enable HTTP/3 on these zones.


Hi all.http/3 quic has not been working for 3 weeks.

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