HubSoft provides several API's to enable your company web site, eCommerce or Pro-Portal. As part of these transactions, message will be passed to you that may have originated within HubSoft or an external service where the message is being passed through. To make it easy to write your own methods or message handling, HubSoft provides you one of the following prefix codes to programatically determine the message you received.

Web Service Message Return Codes
TAX	Error with external tax service, such as address validation within Avalara.
QNA	Quantity not avaliable - In this case, the error message will contain SKU in the format: SKU: error message. This is used when transacting both sales tax and credit card transactions.
CRD	Credit card processing error. Error code will be embedded in the message: ErrorCode: error message.
QLP	Quantity Limit Program - This indicates that the user is attempting to purchase more products than are allowed by the program purchase limits.
QLE	Quantity Limit Exceeded - This indicates that the user is attempting to purchase more than their promotional program limits allow.
INF	Item not found - In this case error message will contain SKU in the format: SKU: Item with SKU.
EPC	Promotion Code has expired. The expiration is based on the local time zone for the company and defined at the 'code-level'.
UPC	Promotion Code has been used. These cases will throw exceptions in web service processing.
IPY	Invalid Payment Method Code. This is returned when a payment type for the program is not available or is not matched.
IPC	Invalid Promotion Code. The access code being provided is not valid or has been consumed.
ION	Invalid Order Number. This occurs for transactions that are updating an existing order and the order number is not matched.
ISM	Invalid Shipping Method Code. This is returned when the shipping method is not available on the program or not matched.
ANF	Invalid Access key Passed. This message is returned when the web service call does not contain a valid web service access key.
UAA	Unauthorized Access. You are invoking from unauthorized location based on your IP address.
WSD	Requested Webservice method is disabled for the access code in the web service.
IOD	Invalid Order Date - This is displayed when the format of the order date is invalid or the order date is not allowed for the start dates on the season.
QEX	Quantity Exceeded - This indicates that the quantity ordered exceeds the available inventory for the product.
ATX	Avalara Tax Error - This is returned if there is a processing error with the Avalara Tax Service.
DSK	Duplicate SKU - The SKU being address to the order line items already exists on the order.
UNK	Unknown Error 0- This is a generic message code for a validation error in the web services. Contact HubSoft to get more direction on this error.
INF	Item Not Found - The SKU that is being added to the order line items can not be matched to a SKU in the product tables.
BNF	Buyer Not Found - The buyer record provided in the order web service was not found.
DPO	Duplicate Purchase Order - This indicates that the purchase order being used on the web service order has already been applied to another order for that dealer.
MPO	Missing Purchase Order - The purchase order valeu is missing and is required to create the order record.
MSC	Missing Store Code - This indicates that the store code was not provided.
ISC	Invalid Store Code - This indicates that the store code or unique identifier within the dealer provided was not found.
IOS	Invalid Order Status - The status value passed in the request is not valid.
IAC	Invalid Account Code - The account or dealer code or unique identifier was not found.
IOT	Invalid Order Type - The order type code passed is not valid.
ISC	Invalid Season Code - The season code provided in the order can not be found.
IBT	Invalid Billing Term - The billing term provided on the order was not found.
ISR	Invalid Sales Rep - The sales rep provided on the order was not found.
ISM	Invalid Shipping Method - The shipping method provided on the order was not found.

You can test for these codes in your return messages. Then write your own translation or application response to these errors. You also receive the detailed error description appended to these codes should want to parse the message and display more detail.