If the call to an API operation of Message Queue for MQTT is successful, ResponseCode=200 is returned to the client. If the call failed, a corresponding error code and its description are returned. You can find solutions based on the error codes listed in the following table.

Token-related error codes

HttpCode Error code Error message Description
404 ApiNotSupport The specified API is not supported. The error message returned because the API operation is not supported.
400 ApplyTokenOverFlow You have applied for tokens too many times. Please try again later. The error message returned because tokens are frequently requested and throttling is triggered by the system. Try again later.
400 CheckAccountInfoFailed An error occurred while checking the account information by the STS token. The error message returned because the account information of the Security Token Service (STS) token failed to be parsed.
400 InstancePermissionCheckFailed An error occurred while validating the permissions of the instance. Please verify the account that created the instance and its permissions settings. The error message returned because permissions on the Message Queue for MQTT instance failed to be verified. Check whether you are granted permissions on the instance.
500 InternalError An error occurred while processing your request. Try again later. The error message returned because the backend service of the Message Queue for MQTT instance is abnormal. Try again later.
400 ParameterCheckFailed An error occurred while validating the parameters. The parameters may be missing or invalid. The error message returned because parameter verification failed. Parameter values may be missing or 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. The error message returned because resource permissions failed to be verified. Check whether you are granted permissions on the instance, topic, and group ID.
500 SystemOverFlow An error occurred while processing your request. Please try again. The error message returned because throttling is triggered by the system. Try again later.
400 InvalidParameter.%s An error occurred while validating the parameter. The parameter may be missing or invalid. The error message returned because parameter verification failed. Parameter values may be missing or invalid.

Group ID-related error codes

HttpCode Error code Error message Description
500 CreateGroupIdError Failed to create GroupId. Try again later. The error message returned because the group ID failed to be created. Try again later.
400 GroupIdAlreadyExsited The specified GroupId already exists. The error message returned because the group ID already exists.
400 GroupIdAlreadyUsedByOtherUsers The current GroupId is used by another user. Please change to a different GroupId. The error message returned because the group ID is used by another user. Try another group ID.
500 InternalError An error occurred while processing your request. Try again later. The error message returned because the backend service of the Message Queue for MQTT instance is abnormal. Try again later.
400 ParameterFieldCheckFailed Failed to validate the parameters. The parameters may be missing or invalid. The error message returned because parameter verification failed. Parameter values may be missing or 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. The error message returned because permissions on the Message Queue for MQTT instance failed to be verified. Check whether you are granted permissions on the instance.
400 InstanceNotFound Failed to find the instance. The instanceId may be invalid. The error message returned because the specified instance is not found.
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. The error message returned because resource permissions failed to be verified. Check whether you are granted permissions on the instance, topic, and group ID.

Topic-related error codes

HttpCode Error code Error message Description
400 ParameterFieldCheckFailed Failed to validate the parameters. The parameters may be missing or invalid. The error message returned because parameter verification failed. Parameter values may be missing or invalid.
400 MqttTopicNumExceeded The maximum number of topics is exceeded. The error message returned because the number of topics on the current instance exceeds the system limit.
400 MqttTopicExist The specified topic already exists. Please check the parameter. The error message returned because the specified topic already exists. Modify the parameter settings.
400 InstanceNotFound Failed to find the instance. The instanceId may be invalid. The error message returned because the specified instance is not found.
400 ResourcePermissionCheckFailed An error occurred while validating the resource permissions. Please check the account that created the instance, topic, and GroupId, and check their permission settings. The error message returned because resource permissions failed to be verified. Check whether you are granted permissions on the instance, topic, and group ID.
400 CreateMqttTopicFailed An error occurred while creating the MQTT topic. Please check the parameter and try again. The error message returned because the topic failed to be created in the Message Queue for MQTT instance. Check the parameters and try again.
400 InstancePermissionCheckFailed An error occurred while validating the permissions of the instance. Please verify the account that created the instance and its permissions settings. The error message returned because permissions on the Message Queue for MQTT instance failed to be verified. Check whether you are granted permissions on the instance.
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. The error message returned because resource permissions failed to be verified. Check whether you are granted permissions on the instance, topic, and group ID.

Rule-related error codes

HttpCode Error code Error message Description
400 ParameterFieldCheckFailed Failed to validate the parameters. The parameters may be missing or invalid. The error message returned because parameter verification failed. Parameter values may be missing or 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. The error message returned because permissions of the Message Queue for MQTT instance failed to be verified. Check whether you are granted permissions on the instance.
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. The error message returned because resource permissions failed to be verified. Check whether you are granted permissions on the instance, topic, and group ID.
400 ResourcePermissionCheckFailed An error occurred while validating the resource permissions. Please check the account that created the instance, topic, and GroupId, and check their permission settings. The error message returned because resource permissions failed to be verified. Check whether you are granted permissions on the instance, topic, and group ID.
400 CreateMqttRuleFailed An error occurred while creating the MQTT rule. Please check the parameter and try again. The error message returned because the rule failed to be created for the Message Queue for MQTT instance. Check the parameters and try again.
400 MqttRuleExist The specified MQTT rule already exists. Please check the parameter. The error message returned because the specified rule already exists. Modify the parameter settings.
400 MqttRuleNumExceeded The maximum number of rules is exceeded. The error message returned because the number of rules for the current instance exceeds the system limit.
400 InstanceNotFound Failed to find the instance. The instanceId may be invalid. The error message returned because the specified instance is not found.

For a list of error codes, visit the API Error Center.