While processing in QuickBooks for Mac with certain transaction security settings enabled, a transaction may be declined in QuickBooks for Mac but appear to continue processing in the Merchant Services Center.
There are Transaction Security Settings relating to the Address Verification Service (AVS) and Card Security Code (CSC) that you may modify in the Merchant Service Center, which affect how certain transactions are handled during processing.
By default, these preferences are set as follows:
If a transaction is rejected due to these settings, QuickBooks for Mac will notify you that the transaction was declined. However, in the Merchant Service Center, the transaction will be appear to be approved, but will be rejected or voided. This means the transaction will not process.
Although it is not recommended, you may allow these transactions to process through without validation of AVS or CSC. To do this, please see Manage Transaction Security Settings in the Merchant Service Center.