I am running a 750G with RouterOS 5.5. I have UPnP set up and working correctly with my Xbox 360. When I do a network test from the Xbox, I get Open NAT. However when I reboot the router, UPnP stops working on the Xbox (when I do a network test I get Moderate NAT). If I remove all interfaces from the IP / UPnP configuration page and add them back again, then everything starts working again.

Anyone else experience this?

I am also having this problem and have tried every solution in the forum. The only thing I haven't tried is downgrading to version 4.17. I'm about to try that now. I've been working on this issue for a while now. Does anyone have any advise on this?

ip upnp export
# jan/02/1970 00:08:16 by RouterOS 5.5
# software id =
#
/ip upnp
set allow-disable-external-interface=yes enabled=yes show-dummy-rule=yes
/ip upnp interfaces
add disabled=no interface=ether1-UplinkTWC type=external
add disabled=no interface=ether4-DLSwitch type=internal
add disabled=no interface=ether2-local- type=internal
add disabled=no interface=ether3-OfficeXB360 type=internal
add disabled=no interface=ether5-WirelessDL type=internal