After trying to start a logical standby by using "ALTER DATABASE START LOGICAL STANDBY APPLY" I got the following error:
- LOGSTDBY status: ORA-01552: cannot use system rollback segment for non-system tablespace 'xxx'
To solve the problem I set the undo management to auto and restarted the apply process.
ALTER system set undo_management=AUTO scope=spfile;
ALTER DATABASE START LOGICAL STANDBY APPLY