No permission to access "~/Sitefinity/default.aspx"

I have a sitefinity web app with a custom membership provider. When i login , it hits custom  membership provider , validates the credentials and  successfully logs us in.

After login i am taken to default.aspx where it shows:

You do not have a permission to access "/SitefinintyWebApp/sitefinity/default.aspx".
Contact your administrator for more information.

How do we set permission to the logged in user? 

A minimum permission to access the pages  for the logged in users unlike admin.