C# SDK Configuration

In my application I installed these package _
ZOHOCRMSDK-2.1

MySql.Data

Newtonsoft.Json

My application is .NET Framework 4.6.2

This is my Initialize class code screenshot. I use self client and scope "ZohoCRM.settings.ALL" for generate GrantToken code. For getting access_token and refresh_token I use postman and call this api "https://accounts.zoho.eu/oauth/v2/token" with GrantToken code, client_id, client_secret header value. With this access token work fine in postman.

But when I called Modules Operations method from sample code it's not work.

Please let me know what's my wrong?