> ## Documentation Index
> Fetch the complete documentation index at: https://docs.methodfi.com/llms.txt
> Use this file to discover all available pages before exploring further.

# mTLS Errors

## Request Errors

The request failed client-certificate validation. These errors occur only for teams provisioned for [mTLS](/2026-03-30/reference/mtls).

These are returned before the request reaches Method's core API, using the standard error envelope.

### `MTLS_CERTIFICATE_REQUIRED`

No client certificate was presented, or the presented certificate failed verification. Returned with HTTP status `401`.

```json theme={null}
{
  "success": false,
  "data": {
    "error": {
      "type": "INVALID_AUTHORIZATION",
      "code": 401,
      "sub_type": "MTLS_CERTIFICATE_REQUIRED",
      "message": "A valid client certificate is required to access this resource. Contact your account administrator about mTLS provisioning."
    }
  },
  "message": "A valid client certificate is required to access this resource. Contact your account administrator about mTLS provisioning."
}
```

***

### `MTLS_CERTIFICATE_NOT_AUTHORIZED`

The certificate is valid but its Subject DN is not authorized for the resolved team. Returned with HTTP status `403`. Confirm the Subject DN registered with Method matches the one on your certificate.

```json theme={null}
{
  "success": false,
  "data": {
    "error": {
      "type": "INVALID_AUTHORIZATION",
      "code": 403,
      "sub_type": "MTLS_CERTIFICATE_NOT_AUTHORIZED",
      "message": "The presented client certificate is not authorized for this team. Contact your account administrator."
    }
  },
  "message": "The presented client certificate is not authorized for this team. Contact your account administrator."
}
```


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