http/3 not working any longer for Cloudfront

Question

In August 2022 it [was announced](https://aws.amazon.com/blogs/aws/new-http-3-support-for-amazon-cloudfront/) support for HTTP/3 for Cloudfront. I spent some time enabling it and testing it yesterday for [our website](https://goto.archi) and it does not serve HTTP/3. I could only get HTTP/2 both on Chrome and on the [http/3 test website from geekflare](https://geekflare.com/tools/http3-test). Anybody else experiencing the same errors.

Answer

HTTP/3 support for Amazon CloudFront was announced in August 2022, so it's relatively new. It is possible that there could still be some compatibility issues or bugs that need to be fixed. If you are unable to get HTTP/3 to work, I would suggest reaching out to Amazon's support team for further assistance.

Answer

Can you verify whether you're getting alt-svc header when getting the output from Http/3 enabled Cloudfront domain?
something like

`alt-svc: h3=":443"; ma=86400`

Also maybe it is worth checking on chome://flags page wether QUIC is enabled (rather than "default" )

http/3 not working any longer for Cloudfront

Contenido relevante