Check that the IP you entered is correct and ping it.
If it's a domain name, ping it to see if you can get through.
The default port of FTP is port 2 1, but it can be modified. Please confirm whether the port is correct. The confirmation method is telnet space ip/ domain name space under cmd. port
If you are prompted that telnet is not xxxxx, please go to the control panel, uninstall the program, turn on the windows function, and then open the telnet client.