Service -> OTEL fail with "Requesting HTTP version 2.0 with version policy RequestVersionOrHigher while unable to establish HTTP/2 connection."

Hello Aspire team,

After a fresh dotnet new aspire-starter, I couldn't see any OTEL data in the dashboard...

After activating the OTEL logs (with OTEL_DIAGNOSTICS.json), i was able to see that the dotnet projects failed pushing data to the OTEL server with the following error:

Exporter failed send data to collector to {0} endpoint. Data will not be sent. Exception: {1}{http://localhost:16159/}{Grpc.Core.RpcException: Status(StatusCode="Internal", Detail="Error starting gRPC call. HttpRequestException: Requesting HTTP version 2.0 with version policy RequestVersionOrHigher while unable to establish HTTP/2 connection.", DebugException="System.Net.Http.HttpRequestException: Requesting HTTP version 2.0 with version policy RequestVersionOrHigher while unable to establish HTTP/2 connection.")
---> System.Net.Http.HttpRequestException: Requesting HTTP version 2.0 with version policy RequestVersionOrHigher while unable to establish HTTP/2 connection.
at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.DiagnosticsHandler.SendAsyncCore(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
at System.Net.Http.Metrics.MetricsHandler.SendAsyncWithMetrics(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
at Grpc.Net.Client.Balancer.Internal.BalancerHttpHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at Grpc.Net.Client.Internal.GrpcCall`2.RunCall(HttpRequestMessage request, Nullable`1 timeout)
--- End of inner exception stack trace ---
at Grpc.Net.Client.Internal.HttpClientCallInvoker.BlockingUnaryCall[TRequest,TResponse](Method`2 method, String host, CallOptions options, TRequest request)
at Grpc.Core.Interceptors.InterceptingCallInvoker.b__3_0[TRequest,TResponse](TRequest req, ClientInterceptorContext`2 ctx)
at Grpc.Core.Interceptors.InterceptingCallInvoker.BlockingUnaryCall[TRequest,TResponse](Method`2 method, String host, CallOptions options, TRequest request)
at OpenTelemetry.Proto.Collector.Metrics.V1.MetricsService.MetricsServiceClient.Export(ExportMetricsServiceRequest request, Metadata headers, Nullable`1 deadline, CancellationToken cancellationToken)
at OpenTelemetry.Exporter.OpenTelemetryProtocol.Implementation.ExportClient.OtlpGrpcMetricsExportClient.SendExportRequest(ExportMetricsServiceRequest request, CancellationToken cancellationToken)}

That was because of my local setup: i'm using PX proxy, and HTTP_PROXY and HTTPS_PROXY were set to http://localhost:3128 (my px port).

By adding HTTP_PROXY="" and HTTPS_PROXY="" in all the launchSettings.json, it finally worked (but it actually took me a lot of time to figure out how to solve this !)

Maybe you could document that somewhere, or add HTTP_PROXY="" in the default template?

It is a pretty common scenario in enterprise to have this kind of proxy setup on your computer.

Thank you for the great job with Aspire, now that it works i can't wait to use it for real !