Oracle Solution for Error ora-38869

ORA-38869: datafile string has been restored from an RMAN backup with undo block compression.

What triggered the Error:

Flashback Database could not flash back the database because a file was restored from an RMAN backup with undo block compression, and the Flashback target was to a time when the missing undo may be needed to open the database.

What should we do to fix it:

Restore an earlier backup of the file and retry the command or Flashback to a later time.