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

# PHP SDK errors and retries

> Exception classes, HTTP status mapping, and automatic retry behavior for transient failures in the Telnyx PHP SDK.

## Handling errors

When the library is unable to connect to the API, or if the API returns a non-success status code (i.e., 4xx or 5xx response), a subclass of `Telnyx\Core\Exceptions\APIException` will be thrown:

```php theme={null}
<?php

use Telnyx\Core\Exceptions\APIConnectionException;
use Telnyx\Core\Exceptions\RateLimitException;
use Telnyx\Core\Exceptions\APIStatusException;

try {
  $numberOrder = $client->numberOrders->create();
} catch (APIConnectionException $e) {
  echo "The server could not be reached", PHP_EOL;
  var_dump($e->getPrevious());
} catch (RateLimitException $e) {
  echo "A 429 status code was received; we should back off a bit.", PHP_EOL;
} catch (APIStatusException $e) {
  echo "Another non-200-range status code was received", PHP_EOL;
  echo $e->getMessage();
}
```

Error codes are as follows:

| Cause | Error Type |
| - | - |
| HTTP 400 | `BadRequestException` |
| HTTP 401 | `AuthenticationException` |
| HTTP 403 | `PermissionDeniedException` |
| HTTP 404 | `NotFoundException` |
| HTTP 409 | `ConflictException` |
| HTTP 422 | `UnprocessableEntityException` |
| HTTP 429 | `RateLimitException` |
| HTTP >= 500 | `InternalServerException` |
| Other HTTP error | `APIStatusException` |
| Timeout | `APITimeoutException` |
| Network error | `APIConnectionException` |

## Retries

Certain errors will be automatically retried 2 times by default, with a short exponential backoff.

Connection errors (for example, due to a network connectivity problem), 408 Request Timeout, 409 Conflict, 429 Rate Limit, >=500 Internal errors, and timeouts will all be retried by default.

You can use the `maxRetries` option to configure or disable this:

```php theme={null}
<?php

use Telnyx\Client;

// Configure the default for all requests:
$client = new Client(requestOptions: ['maxRetries' => 0]);

// Or, configure per-request:
$result = $client->numberOrders->create(
  phoneNumbers: [['phoneNumber' => '+15558675309']],
  requestOptions: ['maxRetries' => 5],
);
```