No HTTP/3 (QUIC) advertisement via Alt-Svc header

Your server does not advertise HTTP/3 (the newest, faster web protocol) via the Alt-Svc header, so browsers stay on the older HTTP/2 and never upgrade. HTTP/3 is roughly a third of global web traffic now. Missing it means slower connections and handshakes, especially on mobile and unreliable networks — a real speed penalty your visitors feel. Turn on HTTP/3 at your CDN or host (Cloudflare, Fastly and Vercel have a toggle). On self-managed nginx 1.25+, add a QUIC listener and an Alt-Svc header advertising h3.

Why this matters

HTTP/3 is roughly a third of global web traffic now. Missing it means slower connections and handshakes, especially on mobile and unreliable networks — a real speed penalty your visitors feel.

How to fix it

Turn on HTTP/3 at your CDN or host (Cloudflare, Fastly and Vercel have a toggle). On self-managed nginx 1.25+, add a QUIC listener and an Alt-Svc header advertising h3.