Information
Do not disable the secure port.
Rationale:
The secure port is used to serve https with authentication and authorization. If you disable it, no https traffic is served and all traffic is served unencrypted.
Solution
Edit the API server pod specification file /etc/kubernetes/manifests/kube-apiserver.yaml on the master node and either remove the --secure-port parameter or set it to a different (non-zero) desired port.
Impact:
You need to set the API Server up with the right TLS certificates.
Default Value:
By default, port 6443 is used as the secure port.
References:
https://kubernetes.io/docs/admin/kube-apiserver/