Oracle Message ORA-19909 - datafile string belongs to an orphan incarnation

ERRORdatafile string belongs to an orphan incarnation
CAUSEEither the specified datafile was restored from a backup that was taken during a period of time that has already been discarded by a RESETLOGS operation, or Oracle cannot identify which database incarnation the file belongs to. The alert log contains more information.
ACTIONRestore a backup of this file that belongs to either the current or a prior incarnation of the database. If you are using RMAN to restore, RMAN will automatically select a correct backup.