x509: certificate signed by unknown authority (possibly because of “crypto/rsa: verification error“

kubeadm init --pod-network-cidr 10.21.0.0/16 \
    --image-repository registry.cn-hangzhou.aliyuncs.com/google_containers

reate pod sandbox: rpc error: code = Unknown desc = [failed to set up sandbox container "5ac64afb8a4f7c98aeeb5f459a80410cb9b180ad92322adc0bfe0b9ce1c81107" network for pod "coredns-6c76c8bb89-jlzgn": networkPlugin cni failed to set up pod "coredns-6c76c8bb89-jlzgn_kube-system" network: error getting ClusterInformation: Get https://[10.96.0.1]:443/apis/crd.projectcalico.org/v1/clusterinformations/default: x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "kubernetes"), failed to clean up sandbox container "5ac64afb8a4f7c98aeeb5f459a80410cb9b180ad92322adc0bfe0b9ce1c81107" network for pod "coredns-6c76c8bb89-jlzgn": networkPlugin cni failed to teardown pod "coredns-6c76c8bb89-jlzgn_kube-system" network: error getting ClusterInformation: Get https://[10.96.0.1]:443/apis/crd.projectcalico.org/v1/clusterinformations/default: x509: certificate signed by unknown authority (possibly because of "crypto/rsa: verification error" while trying to verify candidate authority certificate "kubernetes")]

The reset process does not clean CNI configuration. To do so, you must remove /etc/cni/net.d
The reset process does not reset or clean up iptables rules or IPVS tables.
 If you wish to reset iptables, you must do so manually by using the "iptables" command.
If your cluster was setup to utilize IPVS, run ipvsadm --clear (or similar)
 to reset your system's IPVS tables.
The reset process does not clean your kubeconfig files and you must remove them manually.
 Please, check the contents of the $HOME/.kube/config file.