Message Oracle ORA-38772 - cannot add datafile string - file could not be created

ERRORcannot add datafile string - file could not be created
CAUSEThe recovery step of FLASHBACK DATABASE encountered the creation of a datafile and could not recreate the file. The error from the creation attempt is displayed in another message. The control file file entry for the file is UNNAMEDnnnnn.
ACTIONUse the ALTER DATABASE CREATE DATAFILE statement to create the file.