Resolved FTP not working

[Catia]

Total newbie here. Just got a virtual server running ubuntu 16 with Plesk Onyx. Everything's great, but I can't make FTP work. It's not an issue with users or passwords, I can't even make an FTP connection to the server. Tried with both Windows 7 FTP client and Filezilla, but neither works. I've read a few things suggesting that the problem might be with the way Plesk sets up either the firewall or ProFTP, but I'm lost. Any suggestions would be greatly appreciated.

 

[Catia]

Never mind... solved my own problem. Port 21 was being blocked by the VPS host (1&1). All better now.