When adding new nodes to the cluster, a token is needed to join the new node to the cluster.
Login into the management node and create a new token:
kubeadm token create --print-join-command
The result is something like this:
kubeadm join 192.168.76.3:6443 --token vcatsw.x589176bunx86udn --discovery-token-ca-cert-hash sha256:35e8c087d7a951747beg3ea5e99c5b1701ac485a019e5474ae1b87c2db52022a