Yes, API permission request is required.
https://devtalk.kakao.com/t/api-how-to-request-permission-for-the-retrieving-list-of-friends-api/56783
Is the owner business account Kakao Talk account?
Kakao Talk account holders can find Kakao Talk friends when they receive API permissions.
However, you and your friend must log in to your app and obtain permission. Did you check it in the guide?