# 12001
source: https://developer.mastercard.com/open-finance-us/documentation/errors/error-codes/12001/index.md

This error occurs when there's an unexpected server error while processing the request.

|             Title             |                                                                                                                         Details                                                                                                                          |
|-------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| **Error Code**                | 12003                                                                                                                                                                                                                                                    |
| **Remediation Category**      | Re-Authenticate or Provide Additional Information                                                                                                                                                                                                        |
| **HTTP Status**               | 409 or 500                                                                                                                                                                                                                                               |
| **Error Type**                | Request Error                                                                                                                                                                                                                                            |
| **Data Connect Alert**        | No applicable alert.                                                                                                                                                                                                                                     |
| **Error Message**             | MFA/OTP Encountered.                                                                                                                                                                                                                                     |
| **Common Causes**             | This error occurs if the end user either fails to provide a response, provides an incorrect response or an expired response to security questions or Multi-Factor Authentication (MFA).                                                                  |
| **Troubleshooting Steps**     | Prompt the end user to attempt to add accounts again entering the correct MFA information. If the end user continues to answer incorrectly they may need to go to their financial institution and update their MFA questions/answers and then try again. |
| **Data Connect Fix Eligible** | No.                                                                                                                                                                                                                                                      |
| **Retriable by End User**     | Yes, the end user will be able to resume the session, once the connection to the selected financial institution is fixed. The end user may need to make several authentication attempts to assist in resolving the error.                                |
| **Access to Latest Data**     | You will be unable to access the latest data for this user's account until the end user resolves the issue.                                                                                                                                              |

[Full Error List](https://developer.mastercard.com/open-finance-us/documentation/errors/error-list/index.md) \| [Account Errors](https://developer.mastercard.com/open-finance-us/documentation/errors/account-errors/index.md)