However, after doing the ‘factory reset’ the App works well.

for (SKPaymentTransaction *transaction in transactions)

{

    NSInteger _value = transaction.transactionState;

    switch (_value){

        case SKPaymentTransactionStatePurchased:

            [self completeTransaction:transaction];

            break;

        case SKPaymentTransactionStateFailed:

            [self failedTransaction:transaction];

            break;

        case SKPaymentTransactionStateRestored:

            [self restoreTransaction:transaction];

            break;