App Store in-app purchase dialog launching too late using Rect Native RNIAP package

I have implemented an In-App purchase(Subscription) in one of my applications using the below package. https://www.npmjs.com/package/react-native-iap

Everything is working fine in Android, but it is working very slow on ios mobiles. It is taking more than 3 minutes to launch the purchase dialog 🙁. I'm unable to figure out the problem in the application. Because of this slowness issue, my application release is on hold. Let me know, any suggestions to resolve this issue.

I have followed the standard implementation from the below youtube tutorial. https://www.youtube.com/watch?v=4JLHRV2kiCU

Note: I'm testing in sandbox mode because in-app is not yet reviewed in App Store.

My e-mail: ssuresh1016@gmail.com