Apple Pay Payment Token

We are integrating Apple Pay in our App and successfully done setup, and getting back Payment Token but still it shows Payment not completed error.

-(IBAction)btnApplePayClicked:(id)sender
{
    if([PKPaymentAuthorizationViewController canMakePayments]) {

        NSLog(@"Woo! Can make payments!");

        PKPaymentRequest *request = [[PKPaymentRequest alloc] init];

        PKPaymentSummaryItem *widget1 = [PKPaymentSummaryItem summaryItemWithLabel:@"Widget 1"
                                                                            amount:[NSDecimalNumber decimalNumberWithString:@"0.99"]];

        PKPaymentSummaryItem *widget2 = [PKPaymentSummaryItem summaryItemWithLabel:@"Widget 2"
                                                                            amount:[NSDecimalNumber decimalNumberWithString:@"1.00"]];

        PKPaymentSummaryItem *total = [PKPaymentSummaryItem summaryItemWithLabel:@"Grand Total"
                                                                          amount:[NSDecimalNumber decimalNumberWithString:@"1.99"]];

        request.paymentSummaryItems = @[widget1, widget2, total];
        request.countryCode = @"US";
        request.currencyCode = @"USD";
        request.supportedNetworks = @[PKPaymentNetworkAmex, PKPaymentNetworkMasterCard, PKPaymentNetworkVisa];
        request.merchantIdentifier = @"merchant.com.*******";
        request.merchantCapabilities = PKMerchantCapability3DS;

        PKPaymentAuthorizationViewController *paymentPane = [[PKPaymentAuthorizationViewController alloc] initWithPaymentRequest:request];
        paymentPane.delegate = self;
        [self presentViewController:paymentPane animated:TRUE completion:nil];

    } else {
        NSLog(@"This device cannot make payments");
    }
}
- (void)paymentAuthorizationViewController:(PKPaymentAuthorizationViewController *)controller
                       didAuthorizePayment:(PKPayment *)payment
                                completion:(void (^)(PKPaymentAuthorizationStatus status))completion
{
    NSLog(@"Payment was authorized: %@", payment); //receiving Payment token
}
- (void)paymentAuthorizationViewControllerDidFinish:(PKPaymentAuthorizationViewController *)controller
{
    NSLog(@"Finishing payment view controller");

    [controller dismissViewControllerAnimated:TRUE completion:nil];
}

Test Card in Sandbox environment

FPAN: 4761 1200 1000 0492
Expiration Date: 11/2022
CVV: 533

After receiving Payment token what should we do? Any ideas/suggestions would be helpful. Thank you