I setup a postgreSQL with istio injected in K8s, and I want to use psql(or a postgreSQL client) to access it from other network so I am tryinng to setup istio-ingressgateway to access it, and setup the related gateway and virtualservice to route the traffic, but get some errors as below. Please help take a look the issue.

"psql: server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request. "

yaml files as below

    cat <<EOF | kubectl apply -f -
    apiVersion: v1
    kind: ConfigMap
    metadata:
      name: postgres-config
      labels:
        app: postgres
    data:
      POSTGRES_DB: usermgt
      POSTGRES_USER: admin
      POSTGRES_PASSWORD: admin2020
    EOF

    cat <<EOF | kubectl apply -f -
    kind: PersistentVolume
    apiVersion: v1
    metadata:
      name: postgres-pv-volume
      labels:
        type: local
        app: postgres
    spec:
      storageClassName: manual
      capacity:
        storage: 1Gi
      accessModes:
        - ReadWriteMany
      hostPath:
        path: "/mnt/data"
    ---
    kind: PersistentVolumeClaim
    apiVersion: v1
    metadata:
      name: postgres-pv-claim
      labels:
        app: postgres
    spec:
      storageClassName: manual
      accessModes:
        - ReadWriteMany
      resources:
        requests:
          storage: 1Gi
    EOF

cat <<EOF | istioctl kube-inject -f - | kubectl apply -f -
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: postgres
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: postgres
    spec:
      containers:
        - name: postgres
          image: postgres:10.4
          imagePullPolicy: "IfNotPresent"
          ports:
            - containerPort: 5432
          envFrom:
            - configMapRef:
                name: postgres-config
          volumeMounts:
            - mountPath: /var/lib/postgresql/data
              name: postgredb
      volumes:
        - name: postgredb
          persistentVolumeClaim:
            claimName: postgres-pv-claim
---
apiVersion: v1
kind: Service
metadata:
  name: postgres
  labels:
    app: postgres
spec:
  ports:
   - port: 5432
  selector:
   app: postgres
EOF

cat <<EOF | kubectl apply -f -
apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: postgres-gateway
spec:
  selector:
    istio: ingressgateway
  servers:
  - port:
      number: 5432
      name: pgsql
      protocol: TCP
    hosts:
    - "*"
EOF


cat <<EOF | kubectl apply -f -
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: psql-vs
spec:
  hosts:
  - "*"
  gateways:
  - postgres-gateway
  tcp:
  - match:
    - port: 5432
    route:
    - destination:
        host: postgres.default
        port:
          number: 5432

EOF