I had a two node cluster in which one was master and another slave. It was running from the last 26 days. Today i tried to remove a node using kubeadm reset and add it again and kubelet was not able to start

cni.go:171] Unable to update cni config: No networks found in /etc/cni/net.d
The binary conntrack is not installed, this can cause failures in network connection cleanup.
server.go:376] Version: v1.10.2
feature_gate.go:226] feature gates: &{{} map[]}
plugins.go:89] No cloud provider specified.
server.go:233] failed to run Kubelet: cannot create certificate signing request: Unauthorized

while the join command is successful

[preflight] Running pre-flight checks.
[WARNING FileExisting-crictl]: crictl not found in system path
Suggestion: go get github.com/kubernetes-incubator/cri-tools/cmd/crictl
[preflight] Starting the kubelet service
[discovery] Trying to connect to API Server "aaaaa:6443"
[discovery] Created cluster-info discovery client, requesting info from "https://aaaaa:6443"
[discovery] Requesting info from "https:/aaaaaa:6443" again to validate TLS against the pinned public key
[discovery] Cluster info signature and contents are valid and TLS certificate validates against pinned roots, will use API Server
[discovery] Successfully established connection with API Server "aaaa:6443"

This node has joined the cluster:

Certificate signing request was sent to master and a response
was received.
The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the master to see this node join the cluster.

IMO the log failed to run Kubelet: cannot create certificate signing request: Unauthorized is the source of the problem, but I am do not know how it is coming and how to fix it.

TIA. I can give more details but I am not sure what all I shall give