Nighthawk M1 Port forwarding not working - and it is not the provider network!

We have a Telstra purchased nighthawk M1 router we want to use as a failover mechanism, but to do so we need to get an inbound redirection going... but I just cannot get it to work!

 

The Telstra sim in question is on the Telstra.extranet APN  - note to anyone else out there trying to do this... usually sims will be on telstra.internet which is a NATtEd private network in IP range 1.x.x.x, so port forwarding will never work on that APN. If you need to do port forwarding you will need to call telstra to have the SIM moved to the telstra.extranet APN also known as code/plan GPTEXB3.  Note also this can only be done on business accounts (as I understand it).  You have to manually add the telstra.extranet APN to the config and reboot for it to take effect.

 

The sim is definitely working... if I whack it into a TP-Link TL-MR6400 LTE router, it works perfectly... I can e.g. port forward port 3389 to an internal destination.

 

Just cannot get it to do the same thing in the Nighthawk router.   There is not much to it... turn it on (reboot) add port and internal IP address to redirect that port to.   Just  does not work.  had someone else run their eyes over it, and they cannot see anything wrong either.

 

Firmware is latest available in the interface (don't have that note on hand).  I have tried a factory reset and started again from scratch.

 

Anyone have any ideas? 

 

Is there any way to talk to support after 90 days for something that would clearly appear to be a bug?

 

Thanks!