Trying to generate access code and refresh token with self client in sanbox

Trying to generate access code and refresh token with self client in sanbox

here is my request what am I doing wrong? I can get it to work in production but not in the sandbox

method: POST
url: "https://sandbox.zohoapis.com/oauth/v2/token?code={code}&grant_type=authorization_code&client_id={client_id}&client_secret={secret}"