Question
“Dropped What does the error message "Dropped message: QoS 0 channel not writable” this error message is writable" signify when observed in the HiveMQ control center.?
Answer
In general, this error happens due to clients not being able to read incoming messages fast enough. Please find further details on https://www.hivemq.com/docs/hivemq/4.9/control-center/analytic.html#channel-not-writable.
If your clients are consuming slowly then you can use shared subscriptions to avoid this scenario or MQTT Addon topics for receiving dropped messagesThe "Dropped message: QoS 0 channel not writable" notification appearing in the HiveMQ Control Center is not indicative of a broker error. As per the MQTT specification, QoS 0 messages have no delivery guarantee and may be dropped. The purpose of this notification is to alert users to potential concerns related to slow-consuming clients.
When your clients are consuming slowly or cannot handle the load on subscribed topics individually then a possible solution is to use shared subscriptions.