SQL Server automatic backup cannot delete expired backup files_PHP tutorial

The database server performs database backup at two o'clock in the morning every day, and at the same time deletes the database backup file from 5 days ago, otherwise the hard disk will burst
The information in the windows log is:
SQL Server Scheduled Job 'DB backup job for DB maintenance plan "Database Maintenance Plan 1". ' (0x2DA54A5BBEFC2B4A874428B91602C52A) - Status: Failed - Invoked on: 2005-09-09 01:00:00 - Message: Job failed.
Schedule 28 (Schedule 1) wakes up the job. The last step to run is step 1 (step 1).
The log given in sql server:
sqlmaint.exe failed [SQLSTATE 42000]
Relevant kb given by Microsoft
http://support.microsoft.com/?kbid=288577
http://support.microsoft.com/kb/303292/EN-US/
It seems that the explanation is confusing.
Later I discovered that one of the original databases to be backed up was offline. As a result, it could not be backed up, nor could it be deleted when it expired. I had no choice but to put it back on my computer.