# Network Response Codes
source: https://developer.mastercard.com/mastercard-send-person-to-person/documentation/response-error-codes/network-response-codes/index.md

Mastercard includes the Network Response Codes (ISO Codes) from the receiving networks in Payment Transfer API 201 / 200 response messages, in fields `network_status_code` and `network_status_description`. The Response Code indicates an issuer's reason for approving or declining a transaction, and it is passed to Mastercard in Data Element (DE) 39 of the issuer's network response message.

The table below lists the main valid codes for Mastercard network messages. Some codes might not be relevant to Mastercard Send. Other codes might be provided and the descriptions might vary depending on the message system and network.

For more information about network response codes, refer to the *DE 39 (Response Code)* section in either of these documents, which are available in the [Technical Resource Center](https://trc-techresource.mastercard.com/) on Mastercard Connect:

* [*Mastercard Network Processing Dual Message Authorization System Guide*](https://trc-techresource.mastercard.com/r/bundle/m_DMAS_en-us/page/d/en-US)
* [*Mastercard Network Processing Single Message System Guide*](https://trc-techresource.mastercard.com/r/bundle/m_SMS_Guide_en-us/page/d/en-US)

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**NOTE:** If the POST API request `decline_details` query parameter is not set to 'true', a declined transaction results in a 402 error response, which will not include these fields. However, subsequent retrieval lookup responses for those transactions, using GET requests, will include these fields.

| ISO Code |                        Description                         |
|----------|------------------------------------------------------------|
| 00       | Approved or completed successfully                         |
| 01       | Refer to card issuer                                       |
| 03       | Invalid merchant                                           |
| 04       | Capture card                                               |
| 05       | Do not honor                                               |
| 08       | Honor with ID                                              |
| 10       | Partial Approval                                           |
| 12       | Invalid transaction                                        |
| 13       | Invalid amount                                             |
| 14       | Invalid card number                                        |
| 15       | Invalid issuer                                             |
| 30       | Format error                                               |
| 41       | Lost card                                                  |
| 43       | Stolen card                                                |
| 46       | Closed Account                                             |
| 51       | Insufficient funds/over credit limit                       |
| 54       | Expired card                                               |
| 55       | Invalid PIN                                                |
| 57       | Transaction not permitted to issuer/cardholder             |
| 58       | Transaction not permitted to acquirer/terminal             |
| 61       | Exceeds withdrawal amount limit                            |
| 62       | Restricted card                                            |
| 63       | Security violation                                         |
| 65       | Exceeds withdrawal count limit                             |
| 70       | Contact Card Issuer                                        |
| 71       | PIN Not Changed                                            |
| 72       | Account Not Yet Activated                                  |
| 75       | Allowable number of PIN tries exceeded                     |
| 76       | Invalid/nonexistent "To Account" specified                 |
| 77       | Invalid/nonexistent "From Account" specified               |
| 78       | Invalid/nonexistent account specified (general)            |
| 79       | Life cycle (Mastercard use only)                           |
| 80       | System not available                                       |
| 81       | Domestic Debit Transaction Not Allowed (Regional use only) |
| 82       | Policy (Mastercard use only)                               |
| 83       | Fraud/Security (Mastercard use only)                       |
| 84       | Invalid Authorization Life Cycle                           |
| 85       | Not declined                                               |
| 86       | PIN Validation not possible                                |
| 87       | Purchase Amount Only, No Cash Back Allowed                 |
| 88       | Cryptographic failure                                      |
| 89       | Unacceptable PIN---Transaction Declined---Retry            |
| 90       | Cutoff is in progress                                      |
| 91       | Authorization System or issuer system inoperative          |
| 92       | Unable to route transaction                                |
| 94       | Duplication transaction detected                           |
| 96       | System error                                               |
| 1Z       | Authorization System or issuer system inoperative          |