# Revoke Last Client Encryption Credential Error
source: https://developer.mastercard.com/mastercard-developers-api/documentation/errors/revoke-last-encryption-key/index.md

Revoking last active client encryption credentials is not allowed.

### Solution {#solution}

Client Encryption credentials cannot be deleted while they are in an active state, and there are no other active credentials of this type in the project. To revoke this credential, the user must first add another Client Encryption credential to their project.

### API Error Response {#api-error-response}

**HTTP code 409**

```JSON
{
  "Errors": {
    "Error": [
      {
        "Source": "DEVELOPERS_API",
        "ReasonCode": "REVOKE_LAST_CLIENT_ENCRYPTION_CREDENTIAL_ERROR",
        "Description": "Revoking last active client encryption credential is not allowed",
        "Details": "Revoking the last Client Encryption credential is not allowed. Please add/activate a different Client Encryption credential first.",
        "Recoverable": false
      }
    ]
  }
}
```

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