Unable to create unit by category

after configuration of settings page, we tried to create unit by category but it did not load the categories and throwing below error message.

Could not load a category list in this page: https://www.amazon.in/gp/product/black-curtain-redirect.html?redirect=true&redirectUrl=https%3A%2F%2Fwww.amazon.in%2Fgp%2Fbestsellers%2F. Please consult the plugin developer.

Can you please let me know if i am missing anything.

Thanks,
Bala