Tracing config in apollo router

I want to enable distributed tracing in apollo router using grpc endpoint. I tried different config to do this but getting issues for the same. How do we send grpc request with headers for api key in it?

      # http:
      #   headers:
      #     x-honeycomb-team: "<key>"
      # grpc:
      #   metadata:
      #       x-honeycomb-team:
      #         - "<key>"
      protocol: grpc
      service_name: "rust-gateway"
      service_namespace: "apollo"
      sampler: 1
      # attributes:
      #   - headers.x-honeycomb-team: "<key>"

Getting below errir
{“timestamp”:“2022-10-21T10:43:12.808023Z”,“level”:“ERROR”,“fields”:{“message”:“OpenTelemetry trace error occurred: Exporter otlp encountered the following error(s): the grpc server returns error (Unknown error): , detailed error message: transport error”},“target”:“apollo_router::plugins::telemetry”}

You might already found out, but you need to fix your endpoint like this endpoint: