I set up two PCs both running LXLE and they are firewalled behind the same router.  I am not concerned about sharing my local IPs here.

Their local addresses are; 192.168.1.48 and 192.168.1.56 I used port 21
I made it simple guest access and apparently it will not connect.  I tried secured passwords and nothing it just keeps timing out.
Is there some additional software to install before using this program?  I feel like I hit a brick wall.  No hurry on an answer, if I figure it out, I will be back to tell you.