When you try to connect your kubernetes cluster using kubectl, you have to provide client-key and certificate. You can use the below given command.
$ kubectl get pods --server https://minikube_IP:8443 --client-key /root/client.key --client-certificate /root/client.crt --cerfificate-authority /root/ca.crt
You can change path of your file accordingly.
For further details, refer to the Kubernetes Training.