Resolve worker nodes failure to join with the Kubernetes cluster

Recently, I created a Kubernetes 1.18 cluster using Amazon EKS service, following the steps listed in my article https://gvasanka.medium.com/how-to-create-a-kubernetes-cluster-using-amazon-eks-da0911ea62e2

Though the Control plane and worker nodes successfully created, I noticed worker nodes haven't joined with the cluster.

kubectl get nodes and kubectl get pods commands were giving empty results.