LM1300 - DMZ not working

[DigitalMaestro]

I cannot get DMZ to work on the LM1300. I have the LM1300 in router mode (since I can't get the bridge mode to work consistently) connected to my broadband router through the WAN port and I have my existing Orbi router connected to the LAN port.  So far everything works great (except that I am in a double NAT situation which frowned upon apparently).  However the issue is that I have certain ports forwarded on the Orbi to grant access to some internal servers.  According to the documentation all I need to do is to put the Orbi in the DMZ of the LM1300 and it should all work fine.  However that is not the case.  I cannot access any of the internal servers from the broadband public IP. If I remove the LM1300 from the equation then everything works fine.

How can I resolve this issue?  All documentation I have read online indicates that, although it is not ideal, placing the Orbi in the DMZ of the LM1300 should work just fine.

Any assistance appreciated.

Lester

[normandingo]

Also haven't been able to get DMZ to work.  I have a GL-X750 from GL-iNet 4G modem that works well and turning on DMZ mode on that device will allow me to use my UDM to port forward. However, on the LM1300, I am unable to get the same effect. Were you able to figure this one out or will we just need to set the port forwarding rules twice but port forward to the static IP of the router?