There is one scenario for that I have been seeking for help to get better resolution/understand.
Scenario : Whenever client is communicating with broker and everything runs smoothing but in between whenever broker goes down and making up the broker then we have to restart the mqtt client other client unable to consume the message. Would like to know why it is happening ?
Based on the scenario described it will depend on how your clients handle reconnections when the broker goes down. Some MQTT clients/libraries will detect unsuccessfully connections and try reconnecting after a defined number of attempts.