Hi,

I built a gRPC API using .NET and packaged it in a Docker container.

Local testing in Postman works fine with HTTP/2 enabled, but once I deploy it to my server, gRPC requests fail.

Postman shows:

Could not load server reflection. Details: 1 CANCELLED: Call cancelled

However, if I hit the endpoint in my browser, I get:

An HTTP/1.x request was sent to an HTTP/2 only endpoint.

which means HTTP/2 is enabled.

Details:

• Framework: .NET 9
• Deployment: Docker container
• Works locally with Postman, fails after deployment with the above error