Galera Cluster not syncing from a standalone Mysql Server
The question comment guess by jerichorivera was absolutely right:


  log-slaves-updates on node1 enabled?


..but you seem to have misunderstood.

log_bin=/var/log/mysql/mysql-bin


(or whatever file basename) to enable writing the binary logs a slave can read from. However, this alone lets the node write empty binary logs (a size of a few hundred bytes) if it is slave on its own. To act as intermediate master, also set

log_slave_updates


in the my.cnf.