Hello Karthik,
The reason behind you are not able to access event viewer is that, you dont have correct permissions to access it.
So, inorder to gain access to event viewer you need to get right permissions.
To do that follow below steps,
Go to your policy , if you are using basic policy then,
edit the policy click on advanced,
go to Global olicy option and check on
and then update and apply, Now you will be able to open event viewer.