Error in SiteWiseEdgePublisher log with MqttModule

I installed AWS Greengrass and AWS SiteWise on a Ubuntu 24.02 machine.

When I inspect the log /greengrass/v2/logs/aws.iot.SiteWiseEdgePublisher.log, I see the following error:

2024-06-21T20:45:28.465Z [INFO] (Copier) aws.iot.SiteWiseEdgePublisher: stdout. [INFO ] 2024-06-21 15:45:28.465 [com.hivemq.client.mqtt-1-1] MqttModule - Disconnected from MQTT broker at 127.0.0.1:1883, because io.netty.channel.AbstractChannel$AnnotatedConnectException: finishConnect(..) failed: Connection refused: /127.0.0.1:1883. {scriptName=services.aws.iot.SiteWiseEdgePublisher.lifecycle.Startup.Script, serviceName=aws.iot.SiteWiseEdgePublisher, currentState=RUNNING}

Why am I getting this error and what should I do about it?

The main reason I was looking at the logs is because I cannot get a measurement to be shown in the new assets I created.