无法从istio访问外部mongo数据库服务器

我正在尝试使用istio和envoy为需要连接到外部mongodB服务器的服务实现服务网格，但是由于某些原因，我的服务无法从istio代理访问外部mongodB服务器

I am trying to implement service mesh using istio and envoy for a service which requires connecting to external mongodB server but for some reasons, my service is unable to reach the external mongodB server from istio proxy

下面是我的服务的网关和虚拟服务配置

Below is the gateway and virtual service configuration for my service

    apiVersion: networking.istio.io/v1alpha3
    kind: Gateway
    metadata:
      name: gtreviews
    spec:
      selector:
        istio: ingressgateway
      servers:
      - port:
          number: 7890
          name: http
          protocol: GRPC
        hosts:
        - "*"
---
    apiVersion: networking.istio.io/v1alpha3
    kind: VirtualService
    metadata:
      name: reviews
    spec:
      hosts:
      - "*"
      gateways:
      - gtreviews
      http:
      - match:
        - uri:
            prefix: "/reviews"
        route:
        - destination:
            port:
              number: 8080
            host: reviews.istio-system.svc.cluster.local

我添加了出口服务条目，但仍然无法正常运行

I added egress service entry but still doesn't work

apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
  name: external-svc-mongocluster
spec:
  hosts:
  - xxx.xx.com
  ports:
  - name: mongo
    number: 27017
    protocol: tcp
  location: MESH_EXTERNAL  

---

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: external-svc-mongocluster
spec:
  hosts:
  - xxx.xx.com
  tcp:
  - match:    
    route:
    - destination:
        host: xxx.xx.com
        port:
          number: 27017
      weight: 100