Posts,Activities,Notes section in Opportunity form is Disabled for some User's

Hi,

I am using CRM Online 2016 Update 1 version.

There are many users in CRM with same or different security roles.

Out of that one user is unable to access Activities,Notes section in Opportunity Form.

I have tried by signing with different user and for that user it is enabled.

By checking the security roles, I could find that these two user's are having same permission level.

Can anyone help me to resolve this?

Thanks in Advance!

Athira.