Codes in the 1xxx range are specific to this integration method.

Check the CODE field on every response. 0000 means the transaction was approved. Any other value indicates a validation error, a setup issue, a network problem, or a card decline. The TEXT field contains a human-readable message.

For card declines from the card network, see Credit Card Declines. For authentication errors (1001, 9128), see Authentication.

Request Validation

Code	Message	Description
`1000`	`FORMAT ERROR`	The transaction message is malformed, required fields are missing, or a value is out of bounds.
`1003`	`DECLINED (CV)`	Card verification check failed.
`1011`	`MISSING AMT` / `ILLEGAL AMT`	`AMT` is missing or has an invalid value.
`1028`	`INVALID OPERID`	`OPERID` is malformed.
`1031`	`MISSING REF` / `INVALID REF LEN` / `BAD CHAR IN REF`	`REF` is missing, too long, or contains invalid characters.
`1032`	Card data error	The card data (number, expiry, CVV) failed validation. The `TEXT` field contains the specific validation message.
`1034`	`INVALID OVERRIDE TID`	Terminal override was rejected.
`1036`	`INVALID INV LEN`	Invoice number is the wrong length.
`1040`	`ONLY PLATFEE OR PLATCHRG` / `TRAN TYPE CANNOT SPLIT`	Both `PLATFEE` and `PLATCHRG` were sent, or a Split was attempted on a transaction type that doesn't support it (`SPLIT` is only allowed on Sale, Completion, Refund, and Force Post).
`1041`	`MISSING ZIP`	The terminal requires a ZIP/postal code for address verification, but the transaction did not include one. Supply a valid `ZIP` on Sale, Auth, and Pre-Auth requests.
`1042`	`INVALID ZIP`	A `ZIP` was supplied but is not a valid US ZIP/ZIP+4 or Canadian postal code.

Authorization and Capture

Code	Message	Description
`1016`	`COMP NO MATCH`	Completion (`TYPE=C`) was attempted but doesn't match a prior Pre-Authorization.
`1017`	`NOT VOIDABLE TYPE` / `VOID NO MATCH`	Void (`TYPE=V`) or Refund Void (`TYPE=M`) was attempted against a transaction that doesn't exist or can't be voided.
`1029`	`MISSING AUTH` / `ILLEGAL AUTH` / `INVALID AUTH`	Force Post (`TYPE=F`) requires an `AUTH` number from a prior Auth Only.
`1035`	`DUPLICATE REF`	A transaction with this `REF` already exists on this terminal. This is the gateway's built-in duplicate protection.

Important: 1035 means your request was received before, and the original transaction's outcome is the authoritative answer. Don't re-submit with a new REF to work around it — query the original transaction via Transaction Query to get the result.

CustomerPay and Platform Billing

Code	Message	Description
`1037`	`USERFEE NOT ALLOWED` / `USERFEE TOO SMALL`	The merchant is not enrolled in CustomerPay, or the `USERFEE` is below the required minimum for the transaction amount.
`1038`	`PLATFEE NOT ALLOWED`	The terminal does not have `ENABLE PLAT FEE` set, or this transaction type does not support Platform Fees.
`1039`	`PLATCHRG NOT ALLOWED`	The terminal does not have `ENABLE PLAT CHRG` set, or this transaction type does not support Platform Charges.

Settlement

Code	Message	Description
`1033`	`NOTHING TO SETTLE`	Settlement (`TYPE=D`) was called but the batch contains no transactions.

Embedded Tokenization

Code	Message	Description
`8601`	`INVALID APIKEY`	The API key passed to `Interpay.tokenize()` is invalid or expired. Request a fresh one from `GetAPIKey`.
`8602`	Card data validation error	Card data submitted to the tokenization endpoint failed validation. The `TEXT` field contains the specific message.

Network and Host

Code	Message	Description
`1098`	`INVALID RESPONSE FROM HOST`	The processing host returned an unexpected response. Retry on the alternate gateway server.
`9102`	`TRAN TIMEOUT` / `GATEWAY CONFIG ERROR`	The transaction timed out before the host responded, or the terminal is misconfigured. Retry; if it recurs, contact [email protected].

Gateway Errors

Code	Message	Description
`9100`	`DATA UPDATE ERROR`	Internal gateway error while recording the transaction. Retry the call.
`9900`	`SYSTEM ERROR`	Unexpected gateway exception. Retry on the alternate gateway server.

How to Handle

1035 Duplicate Reference — critical for idempotent retry logic. Never re-submit with a new REF. Query the original transaction instead.
Validation errors (1000, 1011, 1028, 1031, 1032, 1034, 1036, 1040, 1041) — bugs in your integration. Fix the request format.
1032 Card data error — user-facing. Show the customer a "please check your card details" message.
Authorization flow errors (1016, 1017, 1029) — logic issues. You're submitting a capture, void, or refund against a transaction that doesn't match the expected state. Verify your state-tracking.
Fee-not-allowed errors (1037, 1038, 1039) — either the terminal isn't configured for this fee type (contact [email protected]) or the transaction type doesn't support fees (see [Transaction Types]).
Embedded Tokenization (8601, 8602) — request a fresh API key via GetAPIKey and prompt the customer to re-enter card details.
Network errors (1098, 9102, 9100, 9900) — retryable. Use exponential backoff and fall over to the alternate gateway server after a timeout.

Credit Card Declines — declines returned from the card network (code 0205).
Hosted Payment Errors — error codes for Customized Checkout and Embedded Components.

Direct Payment Errors