SSRS Subscription Error: SQL Server Agent was unable to start

When I tried to start SSRS subscription to send weekly reports by e-mail where the prerequisites for SSRS subscription is to be sure that SQL Server Agent is working,so that I opened SQL Server Management Studio to check SQL Server Agent status but unfortunately it stopped !

sqlagent

It’s ease of cake  to start SQL Server Agent by right click and select start ! but In my case when I tried to start it I got the following information dialog

unabletostartagent

Cause: Continue reading SSRS Subscription Error: SQL Server Agent was unable to start