Non-purchased modules - Interface Tabs 2.0
Items not active on an account should be visually greyed or distinguished in some way.
And the messages of "you don't have access" or "this page doesn't exist" make the platform appear broken to a user unfamiliar with how the sales/access process works.
Let's replace that language with something proactive—the module's benefits, links to learn more, a call to action suggesting they contact their platform owner to express interest in utilizing that module, etc.