SDKBox IAP sdkbox.IAP.purchase failure code ,what does it mean

Services 3rd-Party
#1

Hi , I am new to SDKBOX IAP.
I can get my product info successfully from Google play but when I make a purchase call ,the failure is “6 error”.
what 's meaning of “6 error” . Where can find the error code meaning?

log:
iap: onFailure:6 error

        onFailure : function (product, msg) {
            //Purchase failed
            //msg is the error message

            self.log("iap: onFailure:" + msg);
#2

I am testing on android and cocos creator v.1.8.0

#3

take a look at this:

https://developer.android.com/reference/com/android/billingclient/api/BillingClient.BillingResponse.html

#4

From Google doc.

### ERROR

int ERROR

Fatal error during the API action

Constant Value: 6 (0x00000006)