无法连接到部署在 Heroku 上的 GRPC 服务器

Question

我很难与部署在 Herkou 上的 gRPC 服务器通信。

这是我使用 NodeJS 在 gRPC 服务器上监听的方式：

server.js

init() {
    let grpcServer = new grpc.Server();
    grpcServer.addService(services.LocationManagementService, LocationManager);
    grpcServer.bindAsync('0.0.0.0:50051', grpc.ServerCredentials.createInsecure(), () => {
        grpcServer.start();
        console.log("GRPC Server Started");
    });
}

其中 LocationManager.js 如下

const LocationManager = {
    updateLocation: (call, callback) => {
        console.log("The Location Update Function Has Being called");
        let locationUpdateResponse = new messages.LocationDataResponse();
        let request = call.request;
        let authParams = request.getAuthParams();
        let locationUpdateTarget = request.getLocationUpdateTarget();
    },
    queryLocation: (call, callback) => {
        let locationQueryResponse = new messages.LocationDataResponse();
    }
}
module.exports = LocationManager;

为 Flutter 生成客户端库并使用如下：

static ClientChannel clientChannel() {
    return ClientChannel(
      myappname.herokuapp.com,
      port:50051,
      options: ChannelOptions(
        credentials: ChannelCredentials.insecure(),
      ),
    );
  }

LocationManagementClient locationManagementClient =
          LocationManagementClient(clientChannel());

但我一直得到的是：

gRPC Error (code: 14, codeName: UNAVAILABLE, message: Error connecting: SocketException: OS Error: Connection timed out, errno = 110, address = myappname.herokuapp.com, port = 32788, details: null, rawResponse: null)

任何见解将不胜感激。

谢谢。