.net Grpc Request protocol 'HTTP/1.1' is not supported

Thanks for the responses. After reading this article I realized I needed to add the Grpc-Web proxy to my app, as this translates an HTTP/1.1 client message to HTTP/2.

The code additions to client and server are explained in this article.

After making these changes/additions my gRPC messaging service is working fine. Importantly - I spent a lot of time trying to figure out how to reference certificates in my call options - but the messaging works fine without a certificate.

I had the same problem and I have sold it with grpc web as a reverse proxy. first of all you should install Grpc.Net.Client.Web on your grpc service project. after that, use middleware.

app.UseGrpcWeb();

then replace your MapGrpcService with this command.

endpoints.MapGrpcService<yourgRPCService>().EnableGrpcWeb();

in ConfigureService method, add bellow commands.

var handler = new GrpcWebHandler(GrpcWebMode.GrpcWebText, new 
                  HttpClientHandler());
services.AddGrpcClient<YourService.YourServiceClient>(options =>
{
    options.Address = new Uri("http://YourServerAddress");
}).ConfigureChannel(o=> {
    o.HttpClient = new HttpClient(handler);
});            

now you should inject your grpc service client and call your method.

@poury saved my life. This worked for me. I have to update my client's code in ConfigureService method and add code below. (Required Grpc.Net.Client.Web package)

services.AddGrpcClient<GreeterService.GreeterServiceClient>(o => { o.Address = new Uri("https://localhost:5001");})
.ConfigureChannel( o => 
{
     o.HttpHandler = new GrpcWebHandler(new HttpClientHandler());
});

Also enabled app.UseGrpcWeb() & endpoints.MapGrpcService<GreeterService>().EnableGrpcWeb(); on your Server's code.

PS: I don't know why, because my client's side is C# also, not a browser?