I'd be interested know people's thoughts and experiences on the cleanest/most professional way to tell a user they don't have access to a particular set of functions. I will have two user groups, sellers and buyers. They will in turn have their own set of pages/functions.
Should a seller stumble across or get a link to a page that tries to use buyer functions should I show them a 404, redirect to another page, tell them they don't have permission or another option?
For example, say you're a buyer user and you have an active session, but you're on google and google my website and it pops up with my website and in the sitelinks it has "sell your item" and you click it. You'd already be validated at my website as you'd have an active session and the system would try to take you the page to sell your item. Then it would realise, that yes this person is logged in, but they aren't a seller they are a buyer user type. How should my website handle this gracefully