Hi Bijay.Swain,
We would probably want to enable logging called Sylink to see the communication between the client and the manager. If all of your other clients are updating I would assume that your manager is updating as well. Just to be sure though, please check the following:
-Open SEPM
-Click ADMIN on the left
-Click Servers in the lower left
-Select Local Site (Sitename) at the top left
-Click Show LiveUpdate Downloads beside the Admin button
-What is in the middle column for Intrusion Preventian Signatures?
If these are up to date I would suggest giving us a call so we can enable to logging and review them for you.