Message Oracle RMAN-06906 - backup of control file was cancelled

ERRORbackup of control file was cancelled
CAUSEThis is an informational message displayed when PARTIAL option of DURATION option was specified on the BACKUP command and backup could not be completed within the given duration time.
ACTIONRun BACKUP command to backup cancelled files, or let the next backup window backup the cancelled files. It should be noted that the files that were skipped in the current job will be given preference to other files for next the BACKUP command with DURATION option.