Hubble relay server doesn't provide ALPN during TLS handshake while establishing a GRPC connection

[AmoghMK]

I have a hubble relay setup with the following configuration:

hubble:
  relay:
    service:
      type: LoadBalancer
  tls:
    server:
      enabled: true
      mtls: true

I extracted ca.crt, client.crt and client.key from secret hubble-relay-client-certs and I'm able to fetch flows using hubble cli with the following:

hubble observe --server tls://<ip>:443 --tls-ca-cert-files ca.crt --tls-client-cert-file client.crt --tls-client-ley-file client.key --tls-allow-insecure

But when I try to do the same from go via grpc client in go, I'm seeing the following error:
"transport: authentication handshake failed: credentials: cannot check peer: missing selected ALPN property"

tlsConfig := &tls.Config {
  InsecureSkipVerify: true,
  ClientCAs: certPool,
  Certificates: []tls.Certificate{clientCertPair},
  NextProtos: []string{"h2"},
}
conn, err := grpc.NewClient(hubbleAddress, grpc.WithTransportCredentials(credentials.NewTLS(tlsconfig)))
client := observer.NewObserverClient(conn)
stream, err := client.GetFlows(ctx, req)