you are probably doing some NAT before your HotSpot gateway. Try to add the public IP of your HS gateway to Hotspot Manager Hosts tab, that should fix the problem.
Edgars
I have placed the MT IP address (private IP network) on my modem/routers DMZ. I can access the MT router from a remote Winbox connection by specifiying the port 8081. (I have a dynamic public IP and I use dyndns.org)
Question 1:
If a host is on DMZ, is the IP still NATed to the internet?
Question 2:
Can I do port forwarding (RADIUS ports) on my modem/router and get a one-to-one connection to the Hotspot Manager?
If any of these will work, it would save me a trip to buy a new modem!