Getting delayed webalerts in Opmanager

Getting delayed webalerts in Opmanager

Hi,
 
I am getting delayed webalerts in Opmanager. we are monitoring some processess running in linux servers.when some processess goes down getting alerts after 5 to 10 mins. If I stop and start the opmanager service then it works fine.
 
what could be the reason?
 
Sam.

                New to ADSelfService Plus?