Hi Bikram,
I am not sure exactly what you mean by giving the e-mail module role, but in order for a user to use the Admin screen of the SMTP Email module, you will need to ensure your user role has been given the 'EmailTemplate.Adminstrator' module role. Here is some documentation on user roles and module roles.
It is possible I have missed your issue here, so can you please be more specific about the problem you are seeing?