JOINER node not syncing


I work with a cluster of 3 nodes (Percona Cluster XtraDB, 5.6). I have a problem with adding other nodes to the cluster. The error occurs when innobackup is executed.
When i try o execute the command on the donor with: innobackupex --user=sstuser --password=sstuser /tmp/ it works fine, but when starting mysql on a JOINER node, innobackup.backup.log on donor shows “Failed to connect to MySQL server: Access denied for user ‘sstuser’@‘localhost’ (using password: YES)”.

Has anybody else had this problem?