These are couple of mistakes which became issues and ended breaking my head to fix them. I am sure others also have face such incidents.
How to resolve aws-iam-authenticator error “could not load/generate a certificate”
aws-iam-authenticator error “could not load/generate a certificate” can be resolved by terminating master node
Using Win 10 server how to create Kubernetes cluster (in AWS) using kops in Existing VPC
You can create kubernetes cluster using kops command in your existing VPC and hosted zone. Kops will create rest of the required AWS resources.