How to make iaps faster on ios.

My App Store submission just got rejected because "in-app purchase buttons are not responsive".
How can I make them react faster to button touch.
I used the basic implementation of unity iaps from this site: https://unity3d.com/learn/tutorials/topics/ads-analytics/integrating-unity-iap-your-game

 

Are they working in your testing in TestFlight? Have you tried with an actual credit card, before pushing live? They generally should only take a few seconds to respond, we are waiting on the store to return the information.