I need to restrict a user, access only on a particualr schema tables only.So I tried following query and login as user1_gmail_com. But I got following error when I try to br
You need to grant access not only to the tables in the schema, but also to the schema itself.
From the manual:
By default, users cannot access any objects in schemas they do not own. To allow that, the owner of the schema must grant the USAGE privilege on the schema.
So either make your created user the owner of the schema, or grant USAGE on the schema to this user.