I have set up a Syncplify.me sftp server, but I can't log in using any ftp client

Question

I setup a Syncplify.me ftps server yesterday using their free license. I followed the instructions on their video and everything seems to be set up correctly. I can login to both the SuperAdmin and the Admin with no problem via my browser. The problem is that I cannot log into the server itself from WinSCP or Terminus. This is my first sftp server, so I'm probably making an obvious mistake.

1) I don't know which hostname am supposed to use to login. I believe the hostname is the same as the 'virtual sftp site name' but when I use it to login, it doesn't work. I get a network timeout error.

SuperAdmin url looks like this: https://xxx.x.x.x:5443/go/#/syncplify/serverdetails

Admin url looks like this: https://xxx.x.x.x:5443/go-virtualsftpsitename/#/syncplify/dashboard

Also, am I supposed to put sftp. (as in sftp.hostname) in front of the hostname when trying to login via WinSCP?

Also, do I have to enter the VFS I created for the server root as the root directory in the advanced settings of WinSCP?

Thanks in advance for any help.