WorkFlow Deffered agent listener and WorkFlow Deffered notification agent listener down

HI,

Everynight  WorkFlow Deffered agent listener and WorkFlow Deffered notification agent listener come down in our system.

We get the below notification when this happens .

COMPONENT_ID    COMPONENT_NAME   COMPONENT_STATUS                                            
------------ --------------------------------------------- ---------------------------                                          
10002      Workflow Deferred Agent Listener DEACTIVATED_SYSTEM                                          
10003      Workflow Deferred Notification Agent Listener  DEACTIVATED_SYSTEM

What might be causing this and what might me remidial steps to avoid this?

Thanks
Ashish Joshi