I have deployed node application in k8s with socket. I used aws NLB with TLS terminate at ingress.

I have tried many solution but still can solve this.

The ingress file is

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: app-node-ingress
  annotations:
    kubernetes.io/ingress.class: nginx
    nginx.ingress.kubernetes.io/websocket-services: app-node-socket
    nginx.org/websocket-services: app-node-socket
    cert-manager.io/cluster-issuer: "letsencrypt-prod"
    
    kubernetes.io/ingress.class: "nginx"
    nginx.ingress.kubernetes.io/proxy-send-timeout: "3600"
    nginx.ingress.kubernetes.io/proxy-read-timeout: "3600"
    nginx.ingress.kubernetes.io/proxy-connect-timeout: "3600"
    nginx.ingress.kubernetes.io/secure-backends: "true"
    nginx.ingress.kubernetes.io/ssl-redirect: "true"
    nginx.ingress.kubernetes.io/proxy-http-version: "1.1"
    nginx.ingress.kubernetes.io/configuration-snippet: |
      proxy_set_header HOST $host;
      proxy_set_header Host $host;
      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header X-NginX-Proxy false;
      proxy_set_header Upgrade $http_upgrade;
      proxy_set_header Connection "upgrade";
      proxy_redirect off;
   
    
  
spec:
  tls:
    - hosts:
        - testdomain.com
      secretName: letsencrypt-prod
  rules:
    - host: testdomain.com
      http:
        paths:
          - path: /socket.io
            backend:
              serviceName: app-node-socket
              servicePort: 8000
          - path: /
            backend:
              serviceName: app-node
              servicePort: 5000

But still cause WebSocket connection to '<URL>' failed: WebSocket is closed before the connection is established.

Any help will be appreciated.