# Error Codes ## Transaction response codes When using our services, you might end up with a transaction that was declined. This is usually signaled by a response with a `TxApproved` value of false and a decline code in the `ErrCode` field. You can then display the `RespMsg` to the user to explain the error. If you want to be able to tell when a specific type of error occurs, you can use our decline code reference and handle them accordingly. ### Global Payments decline codes These codes are used when processing transactions through the Global Payments system. For Global Payments transaction decline codes, see[Global Payments Testing](/documentation/testing/global-payments-testing.md#decline-codes). ### First Data decline codes These codes are relevant when dealing with transactions processed by First Data. For First Data transaction decline codes, see [First Data Testing](/documentation/testing/first-data-testing.md#response-codes). ### ACH decline codes These codes are specifically for Automated Clearing House (ACH) transactions. For ACH decline codes, see [ACH Testing](/documentation/testing/ach-testing.md#complete-list-of-return-codes). --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.number.tech/documentation/resources/error-codes.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.