HTTP/2 Disabled by Default in Nginx 1.19 – Need Explicit http2 Flag
Problem Locally the server runs Nginx 1.15, where a simple listen 443 ssl directive implicitly enables HTTP/2. The same configuration is deployed to production, which uses Nginx 1.19. In this newer version HTTP/2 is no longer enabled by default, so clients that expect HTTP/2 fail to negotiate the protocol, causing degraded performance and compatibility issue
nginx