Some providers expect to send extra parameters (e.g. HubSpot expects the client_id to be present) to the token exchange endpoint, similar to the auhtorization URI.
Isn't the client_id added automatically in the request() method? If you set your authenticationMethod to client_secret_post, the client_id (and client_secret, if provided) are added to the request body.
Some providers expect to send extra parameters (e.g. HubSpot expects the
client_id
to be present) to the token exchange endpoint, similar to the auhtorization URI.