At Systems Online we use secure FTP whenever possible.
There are 2 channels in FTP communications: DATA channel and COMMAND channel. Depending on your security settings for COMMAND channel, FTP client uses tcp/ip connections with ports 21 or 990. Directory listings and file transfers go via DATA channel.
Some servers use port 20 for DATA channel, but because we have multiple clients, who work with our server simultaneously and who have firewalls and require 'passive' mode, our server is creating tcp/ip connection for DATA channel for the client to connect to one of the ports in range 23000-23100.
Please, contact your network administrator in order to get access to the ports specified: 21, 990, 23000-23100 for the machine IP where you are connecting. For example: in your FTP connection data you will see a machine.domain usually something like: machine.sysonline.com where machine references a specific device.
After this, please, try to connect under either secured, TLS or secured, SSL account in order to access the latest products updates