mTLS configuration between ALB and Traefik

We are using traefik as ingress controller in our AWS EKS cluster. Our traefik pods are present in a private subnet and we have an Application LoadBalancer listening on HTTPS:443 in a public subnet in the VPC same as our EKS cluster.
We have few rules configured in ALB based on hostname and path which is forwarding traffic to a HTTP target group whose targets are the traefik pods. We are trying to change this and use HTTPS protocol for the target group to achieve a more secure communication. But when we change the target group to HTTPS we are getting "502 Bad Gateway" . We have followed the documentation and added tls certificate as secret in ingress manifest present in traefik namespace and as well as ingressroute in project namespace, but still we get the same error.

When we are receiving 502 bad gateway , this is the log in traefik pods -
traefik {"level":"debug","msg":"http: TLS handshake error from tls: no certificates configured"

Please let us know if it is feasible to use HTTPs target group in this case or not. If it is possible are we missing something here.