aws-load-balancer-controller: Internal load balancer throws curl: (52) Empty reply from server

I exposed a k8s service using internal load balancer using annotation kubectl patch svc argo-server -n argo -p '{"metadata": {"annotations": {"service.beta.kubernetes.io/aws-load-balancer-internal": "true"}}}'

It worked for past 6 months with EKS k8s 1.17 but stopped working with EKS K8s upgrade to 1.19 and giving me (52) Empty reply from server for curl.

I tried service.beta.kubernetes.io/aws-load-balancer-internal: "0.0.0.0/0" and service.beta.kubernetes.io/aws-load-balancer-scheme: "internal" both gives same error.

I see external ip is exposed with service.beta.kubernetes.io/aws-load-balancer-internal: "true" but unable to access it

kubectl get svc argo-server -n argo                                                                                                          
NAME          TYPE           CLUSTER-IP       EXTERNAL-IP                                                                        PORT(S)          AGE
argo-server   LoadBalancer   172.20.135.242   internal-ae99b272671214b38bba978529ccc81f-1242061336.us-east-1.elb.amazonaws.com   2746:32105/TCP   11h

❯ curl http://internal-ae99b272671214b38bba978529ccc81f-1242061336.us-east-1.elb.amazonaws.com:2746/
curl: (52) Empty reply from server

P.S - EKS k8s version - 1.19

Any suggestion?