ORA-65093: multitenant container database not set up properly

While starting a container database or mounting a standby container database you may encountered Error: ORA-65093: multitenant container database not set up properly

RMAN-11003: failure during parse/execution of SQL statement: alter database mount standby database
ORA-65093: multitenant container database not set up properly

Solution is add the parameter enable_pluggable_database=true and restart the instance,

enable_pluggable_database=true

Hope this helps…