On your server's Settings page, you can change basic details like name and IP address of your server.
You can change the server name in this section, meaning how WPJack will reference the server.
On certain occasions, cloud providers can change the server's IP address. When this happens, insert the correct IP address in this form.
If WPJack has the wrong IP, it won't be able to connect to the server thus WPJack won't be able to manage the server.