#TIMESTAMP You have enabled keyring plugin. SST encryption is mandatory. Please enable pxc_encrypt_cluster_traffic. Check https://www.percona.com/doc/percona-xtradb-cluster/8.0/security/encrypt-traffic.html#encrypt-sst for more details.
I believe it should be:
" https://docs.percona.com/percona-xtradb-cluster/8.0/encrypt-traffic.html#encrypt-sst-traffic "