Error when exporting to an HTTP endpoint using gRPC

[BlueHtml]

Hi,

I'm encountering an error when exporting to an HTTP endpoint using the gRPC protocol, as shown below:

2025-06-30T13:03:56.9691647Z:HTTP request to {0} failed. Exception: {1}{http://tracing-analysis-dc-bj.aliyuncs.com:8090/opentelemetry.proto.collector.trace.v1.TraceService/Export}{System.Net.Http.HttpRequestException: Requesting HTTP version 2.0 with version policy RequestVersionExact while unable to establish HTTP/2 connection.
   at System.Net.Http.HttpConnectionPool.ThrowGetVersionException(HttpRequestMessage request, Int32 desiredVersion, Exception inner)
   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.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
   at System.Net.Http.HttpClient.<SendAsync>g__Core|83_0(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationTokenSource cts, Boolean disposeCts, CancellationTokenSource pendingRequestsCts, CancellationToken originalCancellationToken)
   at OpenTelemetry.Exporter.OpenTelemetryProtocol.Implementation.ExportClient.OtlpExportClient.SendHttpRequest(HttpRequestMessage request, CancellationToken cancellationToken)
   at OpenTelemetry.Exporter.OpenTelemetryProtocol.Implementation.ExportClient.OtlpGrpcExportClient.SendExportRequest(Byte[] buffer, Int32 contentLength, DateTime deadlineUtc, CancellationToken cancellationToken)}

The OTel environment variables are as follows:

set OTEL_EXPORTER_OTLP_ENDPOINT=http://tracing-analysis-dc-bj.aliyuncs.com:8090
set OTEL_EXPORTER_OTLP_PROTOCOL=grpc

My NuGet package versions are as follows:

    <PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.12.0" />
    <PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.12.0" />
    <PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.12.0" />
    <PackageReference Include="OpenTelemetry.Instrumentation.Http" Version="1.12.0" />

.NET Runtime Version: net8.0