Possible problems:

1. If the rocketmq storage folder is not created, the broker log will also report an error

2. If the topic is not automatically created, the IP accessed at startup is different from the IP in broker.config configuration, and an error will be reported.

 nohup sh mqbroker -n localhost:9876 autoCreateTopicEnable=true &

3. If the client version is inconsistent with the MQ version, an error may be reported