i am using node js trying to run grpc in kubernetes cluster env. localy without kubernetes its working fine.the server side is listening to : '0.0.0.0:80' and client tries to connect via: http://recommended-upgrades-qa-int. in the kuberenets i get the following error:

ERROR failed to get via grpc the getRecommended Error: 14 UNAVAILABLE: Connect Failed endpoint:http://<K8S_SERVICE_NAME>
ERROR: Recommendations fetch error: Error: 14 UNAVAILABLE: Connect Failed severity=error, message=failed to get via grpc the getRecommended Error: 14 UNAVAILABLE: Connect Failed endpoint:http://<K8S_SERVICE_NAME>

server side:

const connectionHost = this.listenHost + ':' + this.listenPort;
server.bind(connectionHost, grpc.ServerCredentials.createInsecure());
logger.info(`Server running at ${connectionHost}`);
server.start();

client side:

RecommendedService = grpc.load(__dirname + '/../../node_modules/@zerto/lib-service-clients/Output/sources/recommendedClient.proto').RecommendedService;
        } catch (error){
            console.log(error);
        }

        this.client = RecommendedService && new RecommendedService(grpcAddress, grpc.credentials.createInsecure());

manefist files:

server side

apiVersion: apps/v1
kind: Deployment
metadata:
  name: server-side-deployment
  namespace: default
spec:
  selector:
    matchLabels:
      app: server-side-deployment
  replicas: 1
  template:
    metadata:
      labels:
        app: server-side-deployment
    spec:
      containers:
      - name: server-side-deployment
        image: (DOCKER_IMAGE_PATH)
        imagePullPolicy: Always
        ports:
        - containerPort: 80

---
apiVersion: v1
kind: Service
metadata:
  name: recommended-upgrades-qa-int
  namespace: default
spec:
  selector:
      app: server-side-deployment
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
      name: http

client side

apiVersion: apps/v1
kind: Deployment
metadata:
  name: client-side-deployment
  namespace: default
spec:
  selector:
    matchLabels:
      app: client-side-deployment
  replicas: 1
  template:
    metadata:
      labels:
        app: client-side-deployment
    spec:
      containers:
      - name: client-side-deployment
        image: (DOCKER_IMAGE_PATH)
        imagePullPolicy: Always
        env:
          - name: RECOMANDED_SERVICE
            value: http://recommended-upgrades-qa-int
        ports:
        - containerPort: 80