A successful OpenAPI call to ApsaraMQ for MQTT returns a ResponseCode of 200. If a call fails, the response includes an error code and a description. The following tables list common error codes and solutions.
Token-related error codes
| HttpCode | Error code | Error message | Description |
| 404 | ApiNotSupport | The specified API is not supported. | The specified API operation is not supported. Verify the API name. |
| 400 | ApplyTokenOverFlow | You have applied for tokens too many times. Please try again later. | Token requests are being throttled due to excessive frequency. Retry later. |
| 400 | CheckAccountInfoFailed | An error occurred while checking the account information by the STS token. | Failed to parse account information from the Security Token Service (STS) token. |
| 400 | InstancePermissionCheckFailed | An error occurred while validating the permissions of the instance. Please verify the account that created the instance and its permissions settings. | Access denied for the instance. Confirm the ownership of the ApsaraMQ for MQTT instance and check the authorization policy. |
| 500 | InternalError | An error occurred while processing your request. Try again later. | An internal error occurred in the ApsaraMQ for MQTT backend service. Retry the request. |
| 400 | ParameterCheckFailed | An error occurred while validating the parameters. The parameters may be missing or invalid. | Parameter verification failed. A parameter may be missing or its value is invalid. |
| 400 | PermissionCheckFailed | An error occurred while validating the resource permissions. Please check the account that created the instance, topic, and GroupId, and check their permission settings. | Access denied for the resource. Check the permissions and authorization policy for the instance, topic, and Group ID. |
| 500 | SystemOverFlow | An error occurred while processing your request. Please try again. | Requests are being throttled. Retry the request. |
| 400 | InvalidParameter.%s | An error occurred while validating the parameter. The parameter may be missing or invalid. | Parameter verification failed. A parameter may be missing or its value is invalid. |
Group ID-related error codes
| HttpCode | Error code | Error message | Description |
| 500 | CreateGroupIdError | Failed to create GroupId. Try again later. | Failed to create the Group ID. Retry the request later. |
| 400 | GroupIdAlreadyExsited | The specified GroupId already exists. | The Group ID already exists. |
| 400 | GroupIdAlreadyUsedByOtherUsers | The current GroupId is used by another user. Please change to a different GroupId. | The Group ID is in use by another account. Specify a different Group ID. |
| 500 | InternalError | An error occurred while processing your request. Try again later. | The ApsaraMQ for MQTT backend service encountered an error. Retry the request. |
| 400 | ParameterFieldCheckFailed | Failed to validate the parameters. The parameters may be missing or invalid. | Parameter verification failed. A parameter may be missing or its value is invalid. |
| 400 | InstancePermissionCheckFailed | An error occurred while validating the permissions of the instance. Please verify the account that created the instance and its permissions settings. | Access denied for the instance. Confirm the ownership of the ApsaraMQ for MQTT instance and check the authorization policy. |
| 400 | InstanceNotFound | Failed to find the instance. The instanceId may be invalid. | The specified instance was not found. Verify the instance ID. |
| 400 | PermissionCheckFailed | An error occurred while validating the resource permissions. Please check the account that created the instance, topic, and GroupId, and check their permission settings. | Access denied for the resource. Check the permissions and authorization policy for the instance, topic, and Group ID. |
For more error codes, see the Error Center.