# AWS IoT errors
<a name="iot-errors"></a>

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This section lists the error codes sent by AWS IoT. 


**Message broker error codes**  

| Error code | Error description | 
| --- | --- | 
| 400 | Bad request. | 
| 401 | Unauthorized. | 
| 403 | Forbidden. | 
| 426 | Upgrade required. | 
| 503 | Service unavailable. | 


**Identity and security error codes**  

| Error code | Error description | 
| --- | --- | 
| 401 | Unauthorized. | 


**Device shadow error codes**  

| Error code | Error description | 
| --- | --- | 
| 400 | Bad request. | 
| 401 | Unauthorized. | 
| 403 | Forbidden. | 
| 404 | Not found. | 
| 409 | Conflict. | 
| 413 | Request too large. | 
| 422 | Failed to process request. | 
| 429 | Too many requests. | 
| 500 | Internal error. | 
| 503 | Service unavailable. |