how to switch on simplified dister recovery,

HI ALL my jobs arecompleted with exception could not understand why my simplified dister recover isturn off is it run only for onetime

i have selected completed drives in which my mdf and ldf files are ,still y it is givng my this error,i have also selected system state and ext and sql backup instance

The backup options or selections for this job have changed since the last time it ran.

Backup- Vishnu\MSSQLSERVER
V-79-40960-37914 - Database ReportServer is configured to maintain transaction logs. Transaction log backups are not being performed. This will result in the log growing to fill all available disk space. Regular log backups should be scheduled or the database should be changed to the simple recovery mode.