# Error codes

You may encounter the following error codes while working with the Omnichannel
API.

| Code | Title | Description |
|---|---|---|
| 499 | Cancelled | The operation is cancelled. |
| 500 | Unknown | Unknown error. |
| 400 | Invalid_Argument | Request contains an invalid argument. |
| 504 | Deadline_Exceeded | Deadline expired before operation could complete. |
| 404 | Not_found | Requested entity was not found. |
| 409 | Already_Exists | Request entity already exists. |
| 403 | Permission_denied | The caller does not have permission. |
| 429 | Resource_Exhausted | Resource has been exhausted (eg.check quote). |
| 400 | Failed_Precondition | Precondition check failed. |
| 409 | Aborted | The operation was aborted. |
| 500 | Internal | Internal error encountered. |
| 503 | Unavailable | The service is unavailable. |
| 401 | Unauthenticated | The request does not have valid authenticated credentials. |