Pub/Sub Lite GRPC - 错误：14 不可用：502：网关错误

如何解决Pub/Sub Lite GRPC - 错误：14 不可用：502：网关错误

我正在尝试使用 grpc 在 NodeJS 中使用 Google Cloud Pub/Sub Lite 服务。但是，我遇到了以下错误：{"code":14,"details":"502:Bad Gateway","metadata":{"internalRepr":{},"options":{}}} 当我尝试在队列中发布消息。

我无法让它工作，有人可以帮忙吗？

这是我的代码：

    async function message() {

const protoDir = "node_modules/google-proto-files/google/cloud/pubsublite/v1/publisher.proto";
const packageDefinition = protoLoader.loadSync(protoDir,{
  includeDirs: [
    protos.getProtoPath('..'),'node_modules/google-proto-files/google/cloud/pubsublite/v1/'
  ],keepCase: true,longs: String,enums: String,defaults: true,oneofs: true
});

const packageObject = grpc.loadPackageDefinition(packageDefinition);
const package = packageObject.google.cloud.pubsublite.v1;
const Publisher = package.PublisherService

var ssl_creds = grpc.credentials.createSsl();
const gAuth = new GoogleAuth({
  scopes: ['https://www.googleapis.com/auth/cloud-platform'],});
  gAuth.getApplicationDefault(function(err,auth) {
    var call_creds = grpc.credentials.createFromGoogleCredential(auth);
    var combined_creds = grpc.credentials.combineChannelCredentials(ssl_creds,call_creds);
    const client = new Publisher('europe-west1-pubsublite.googleapis.com',combined_creds)

    const initial = {
        topic:'projects/projectId/locations/europe-west1-b/topics/poc-topic',}

    var pub = {
        request_type: initial
    }
    const pubb = client.Publish(function(err,res) {
      console.log("ERROR --> " + err)

    });
    
    pubb.on('data',function(data) {
        console.log("Data --> " + data);
    });
    pubb.on('end',function() {
      console.log('end ')
    });
    pubb.on('error',function(e) {
      console.log('Error ' + e)
    });
    pubb.on('status',function(status) {
      console.log('Status ' + JSON.stringify(status))
      pubb.write(pub);
    });
    
  });
}