mqtt process loop error :4 라고 되어 있는데 어떻게 해결 해야 하나요?
search for mqtt_transport_yield gives no results. You must look into the source you have to identify the cause of the error. MQTT 3.1.1 defines connect error 4 as “Connection rejected for damaged username or password - The data in the username or password is in the wrong format”, or it may just happen that connection was dropped.
