为啥我的设备Topic里面没有东西呀

而且一直串口一直卡在Attempting MQTT connection...Attempting MQTT connection...Attempting MQTT connection...Attempting MQTT connection...Attempting MQTT connection...Attempting MQTT connection...Attempting MQTT connection...Attempting MQTT connection...Attempting MQTT connection...

没有连接成功之前，设备的topic列表是空的，可以从产品的topic列表查看。一直连不上MQTT的问题，复位板子没用的话就检查代码里的参数改对了没有，可以参考这个帖子https://mc.dfrobot.com.cn/thread-308441-1-1.html