Go-Paho MQTT中的QoS 2,重新连接后仅发送120个存储数据

I used Paho MQTT for Golang with QoS 2 to publish data. When my device disconnect, data stored in a directory. After reconnect, my device publish data to broker, but only 120-first of data publish to broker. I checked in the storage directory, there are some data left in that directory.

my MQTT setting options

opts = mqtt.NewClientOptions()
opts.AddBroker("tcp://" + c.ServerHost + ":" + c.ServerPort).SetClientID("myclientid/" + c.LocoID).SetMaxReconnectInterval(1 * time.Minute).SetAutoReconnect(true).SetMessageChannelDepth(150)
opts.SetUsername("myusername").SetPassword("mypass")
opts.SetCleanSession(false).SetStore(mqtt.NewFileStore("/home/locotrack/locotrack/storeMQTT")) 

Did i miss the configuration setting on that client options?

Thanks for your help