Why Does the Data Destination of a Rule Engine Fail to Receive Messages from My Device After It Is Connected to LINK?

The possible causes are as follows:

• An incorrect inbound rule is added to your security group.

  Click Instance Information and locate the target security group. Click the security group name to access its details page. Then, add an inbound rule based on the parameters listed in Table 1.

  Table 1 Security group parameters

  Parameter	Port
  Port for accessing MQS through an intranet	9092
  Port for accessing MQS through an intranet in SSL mode	9093
  Port for accessing MQS through a public network	9094, 9095, and 9096
  Port for accessing MQS through a public network in SSL mode	9095, 9096, and 9097
  Port for accessing MQS through RESTful APIs	9292

• The topic is incorrectly configured.

  You need to use a topic that has permission to publish messages. Check whether your topic has the publish permission. You can find the name of the topic where the fault occurs in the Topic Name column, and then check whether the topic has the publish permission in the Topic Type column. If a topic does not have the publish permission, the device cannot send messages to the destination of the rule engine.

  To solve this problem, you can configure a topic of the Publish type on the device so that the device can send messages to the destination.

• The first default rule of the security group is deleted.

  When a security group is created, the system automatically generates an inbound rule that allows the destination of the rule engine to receive messages from all devices. If you delete this rule without creating other inbound rules, the entire security group will lack inbound rules. As a result, the destination of the rule engine cannot receive messages from the device.

  You can add inbound rules to solve this problem. If the rule engine is required to receive information from a specific device, you can add an inbound rule and set the port range to the port of the specific device. If the rule engine is required to receive information from all devices, you can add an inbound rule and set the port range to All.

• The topic is deleted.

  The rule engine needs to forward messages to a specified topic. If the topic is deleted unexpectedly, messages fail to forwarded to the topic.

  To solve this problem, create a topic and configure the topic in the rule engine. When you create the topic, you need to specify the publish or subscribe permission for the topic.