When going through the standard OAuth2 flow, "invalid_client" is returned after the user clicks "Grant".
Custom Applications with users going through the standard OAuth2 flow.
Steps To Resolve
- Make sure the client_id is properly spelled when the user is first directed to the OAuth2 URL. It's not uncommon to miss a letter or number at the end.
- Pipe parameters (e.g. "|") in the redirect_uri are not supported and will also generate this message.
The client_id in the OAuth2 URL must be a valid client ID, and the rest of the redirect_uri must be properly formatted.