That would suggest your oAuth token is not a user Access token and has no User associated with it.
Additionally the token in my example is from the docs and invalid
IE: cfabdegwdoklmawdzdo98xt2fo512y is not a valid token
(Also the docs example hasn’t been updated to note the requirement of the ClientID to be present Requiring OAuth for Helix Twitch API Endpoints updated my reply above for the client-id inclusion )
Example and working code/demo using implicit auth at https://github.com/BarryCarlyon/twitch_misc/tree/master/authentication/implicit_auth