React-native-iap: validateReceiptAndroid always returns undefined

Version of react-native-iap

2.4.0-beta6

Version of react-native

0.57.8

Platforms you faced the error (IOS or Android or both?)

Android

Expected behavior

When I try to use validateReceiptAndroid, I expected an object like this:
{
"kind": "androidpublisher#subscriptionPurchase",
"startTimeMillis": long,
"expiryTimeMillis": long,
"autoRenewing": boolean
}

Actual behavior

validateReceiptAndroid always returns undefined

Tested environment (Emulator? Real Device?)

Real Device (Moto G5 Plus)

Steps to reproduce the behavior

let accessToken = "460530446560-9ueadkhvjrh1rh93roaso56fnu49ir78.apps.googleusercontent.com"; (clientId OAuth 2.0 from google api)
const purchase = await RNIap.buySubscription(itemSubs[sku]);
let decodedReceipt = await RNIap.validateReceiptAndroid('com.ourPackage', purchase.productId, purchase.purchaseToken, accessToken, true);