I don't know why some would be able to connect and others not. It is the same network that was working for your VMs, so the only factors here are your network config (mainly port range forwarding), and your server config file. Maybe post your server config file (minus any passwords)? If you are setting the IP fields that have a comment above them not to change them, then that could definitely cause odd issues. I do networking for a living, so I am sure we can figure this out
