I have try to test the API (https://sellingpartnerapi-na.amazon.com/authorization/v1/authorizationCode) by postman. Although I have input the params and authorization with AWS signature, the message "Access token is missing in the request header." is shown. what are the fields do I need to put in the header tab?
P.S. The Session Token field is empty now, do I need to assign it and how to find it?