Hi Jaya,
If you are checking from security.logs Check how many server you are having in the server list.
bg services can be deployed in separate server.
Select the other servers in the list and look for the bg-ca.log files for job failure related errors.
If you have Clarity System Administrator access select the properties of the server and go to the Background link and check whether Run Job Scheduler check box is selected to confirm in which server the bg services is deployed.
Run the command Service status all command in all the CA PPM Servers to confirm in which server bg service is deployed.
Once you get the bg server information check the bg-ca.log file for all job related failure infromation.
Regards,
Arun