[Solved] Can't join Existing kubernetes cluster could not find a JWS signature in the cluster-info ConfigMap for token ID

 [Error] 

error execution phase preflight: couldn't validate the identity of the API Server: could not find a JWS signature in the cluster-info ConfigMap for token ID "nwuv63"

To see the stack trace of this error execute with --v=5 or higher

[Cause]

The token which you are using in kubeadm command to join the worker node to the existing kubernetes cluster has expired and you will need to generate a new valid token on the master node

[Resolution]

 [centos@k8smaster ~]$ kubeadm token create  
 mq4znm.pb5so8esum3watjl  

You can check the details of the token like its expiring time as

 [centos@k8smaster ~]$ kubeadm token list  

 TOKEN                    TTL     EXPIRES               USAGES                  DESCRIPTION        EXTRA GROUPS  
 mq4znm.pb5so8esum3watjl  23h     2021-07-24T18:26:37Z  authentication,signing  <none>             system:bootstrappers:kubeadm:default-node-token