This problem is because the server name cannot be correctly resolved to the server IP address, so you need to open the hosts file in the folder C: \ Windows \ System32 \ Drivers \ etc to bind the server name and IP address, so that when the client connects to the server with the server name, it will automatically resolve to the server with the IP address bound, so there is no problem that the host cannot be found. In other words, if you change the IP address of the host at this time, this problem will appear again. You can change the IP address to the updated IP address in the hosts file, and then you can connect again.