You are trying to use an App Access Token, which is not linked to a user. You must use the Implicit or Authorization Code Flow, not Client Credentials.
I could write a longer paragraph, but I already have here:
Additionally, @Dkamps18 pointed out elsewhere that your call is missing a Content-Type header. It should be set to application/json for how you are sending the data. (That will be why it can’t find your parameters and complains about not having any parameters passed to the endpoint.)