Access Mail from API

Access Mail from API

Hi Team,
I've been trying to use the Zoho Mail API to test in the dev environment. I've successfully obtained an access token from this link " https://accounts.zoho.com/apiauthtoken/create?SCOPE=ZohoMail/ZohoMailAPI"
but when trying to use it for authorization i'm getting weird errors. Everything works fine in postman but in c# the zoho mail resource server returns 404/400.