In cases where the Flipkart Token and Token Secret are not automatically generated after clinking on Enable API, You can manually get the details just buy following the below mentioned steps
Steps to get your Flipkart API details
1) Click on Seller APIs - Developer Admin and login which you Flipkart seller account credentials
2) Click on Register New Application
3) Enter the Application Name and Application Description as Seller API
4) In the drop down for Application Type choose self_access_application and click on Register Application.
5) Once the Application generates the API details, the page will redirect with the Application ID and the Application Secret.
6)Copy the Application ID and the Application Secret and past it in the space provided in Flipkart Settings on Browntape.
So just by doing a few steps you can manually get the Flipkart seller APIs.