The Facebook App is only used to authorize the channel and generate the tokens to publish content. It's not used by your regular site users.
Even though Facebook Apps are likely to work in the same way, Facebook is frequently updating its Platform and changing the API, permissions, policies, etc. As a result, Facebook is migrating Apps and changing settings from its side, and it has impacts on the daily operations of every App.
Please, note that you have configured your App with
and you are authorizing from a different domain (wassenaarders.nl, with no www), try to authorize from the same configured domain.