go to post Michele De Chiffre · Aug 23, 2022 I solved it by make the following changes: 1. set the client to use form encoded body as authentication type (in the OAuth 2.0 setup of the Management Portal) 2. Move the grant_type parameter to the querystring (like https://[oauth-server-adress]/token?grant_type=authorization_code 3. make sure the POST request used form encoded body as content type