> For the complete documentation index, see [llms.txt](https://docs.idlayr.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.idlayr.com/products/risk/sim-swap/error-codes.md).

# Error codes

{% hint style="info" %}
**Backend API** · GA
{% endhint %}

Errors specific to SIM Swap. Two classes:

* **HTTP-response errors** — returned on the synchronous response. RFC 7807 body with an `error_code`.
* **Terminal-state error codes** — carried in the SIMSwapCheck resource body when `status` is `ERROR`. Because SIM Swap is synchronous, terminal-state errors arrive in the same HTTP response as the create call, alongside `status: ERROR`.

This page lists only SIM Swap-specific codes. For the canonical, cross-product error catalogue with full semantics — see the [API Reference](https://docs.idlayr.com/api-reference).

## HTTP-response errors

<table data-header-hidden="false" data-header-sticky><thead><tr><th width="92.69921875">HTTP</th><th width="221.72265625">Error code</th><th>When</th></tr></thead><tbody><tr><td>400</td><td><code>phone_number_invalid</code></td><td>The phone number isn't in a valid international format. Use E.164 (e.g. +14155552671).</td></tr><tr><td>400</td><td><code>mno_not_supported</code></td><td>The MNO doesn't support SIM Swap for this number</td></tr><tr><td>400</td><td><code>bad_request</code></td><td>Malform request body</td></tr><tr><td>401</td><td><code>unauthorized</code></td><td>Your authentication token is missing, invalid, expired, or couldn't be verified. Get a new token and retry.</td></tr><tr><td>403</td><td><code>invalid_scope</code></td><td>Your credentials are valid but don't have permission for this endpoint or project. Request the correct scope for your token.</td></tr><tr><td>404</td><td><code>check_not_found</code></td><td>We couldn't find a check with this ID — it may be incorrect, expired, or already removed.</td></tr><tr><td>412</td><td><code>not_mobile_ip</code></td><td>This request isn't coming from a mobile data connection, which this check requires.</td></tr><tr><td>429</td><td><code>too_many_requests</code></td><td>The Project's rate limit has been exceeded.</td></tr><tr><td>500</td><td><code>internal_server_error</code></td><td>An error occurred inside IDlayr</td></tr><tr><td>504</td><td><code>mno_timeout</code></td><td>The MNO query timed out</td></tr></tbody></table>

## Terminal-state error codes

Returned on the SIMSwapCheck resource when `status` is `ERROR`. The `error_code` field carries one of:

<table data-header-hidden="false" data-header-sticky><thead><tr><th width="222.16015625">Error code</th><th width="102.2265625">HTTP</th><th>Meaning</th></tr></thead><tbody><tr><td><code>not_mobile_ip</code></td><td>412</td><td>This request isn't coming from a mobile data connection, which this check requires.</td></tr><tr><td><code>mno_not_supported</code></td><td>422</td><td>We don't currently support this mobile operator.</td></tr><tr><td>🆕 <code>mno_not_enabled</code></td><td>422</td><td>This mobile operator isn't yet enabled for your project. Check your Approved Networks page, or request approval.</td></tr><tr><td>🆕 <code>mvno_not_supported</code></td><td>200 (Error field)</td><td>This phone number is from Mobile Virtual Network Operator that is not supported.</td></tr><tr><td><code>mno_response_error</code></td><td>200 (Error field)</td><td>The mobile operator's system sent back a response we couldn't understand.</td></tr><tr><td><code>mno_no_data_available</code></td><td>200 (Error field)</td><td>The mobile operator isn't able to share the information needed for this check.</td></tr><tr><td><code>mno_user_not_found</code></td><td>200 (Error field)</td><td>This phone number isn't recognized by the mobile operator for this check.</td></tr><tr><td><code>mno_server_error</code></td><td>200 (Error field)</td><td>The mobile operator's system returned an unexpected error.</td></tr><tr><td><code>internal_error</code></td><td>500</td><td>Something went wrong on our end. Retry, and contact support if it persists.</td></tr><tr><td>🆕 <code>service_unavailable</code></td><td>503</td><td>We're having a temporary issue on our side.</td></tr><tr><td><code>mno_timeout</code></td><td>504</td><td>The request to the mobile operator's system timed out.</td></tr></tbody></table>

In practice, a `status: ERROR` arrives synchronously on the create response — there is no async error path. Treat it as a "couldn't determine SIM-change state" signal and route to your fallback path.

## How to handle errors in your business logic

A `status: ERROR` is not the same as `no_sim_change: false`. The first means "we couldn't determine"; the second means "we determined a SIM change happened." Don't conflate them — your risk policy should treat them differently:

* `no_sim_change: true` — pass.
* `no_sim_change: false` — block, step up, or flag, per your policy.
* `status: ERROR` — fall back to an alternative verification path. Don't assume safe and don't assume fraud.


---

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