Generally speaking, the 502 port system will be reserved for Modbus TCP communication protocol, so are there any other processes using Modbus TCP protocol still in use? You can check it yourself first. If yes, please turn it off first.

Anyway, I hope it's violent if I don't find any problems. In short, we will find out who is occupying it and then terminate the process directly from the task manager. The specific method is to open the console, enter netstat -ano, then find the PID occupying this port, find the corresponding PID in the task manager, and then kill it.

Codemap is a little tired. I found you a post with similar problems. You can refer to it!