Nighthawk M1 - Data offloading won't work

Hi and thanks for all the suggestions and help. Unfortunately: doesn't still work.
I did the simplest thing and changed the router's IP from 192.168.1.1 to 192.168.1.2. After that I couldn't even connect  to the Dashboard anymore, neither with the Netgear App or with iPad or a laptop. Trying to connect to the Dashboard either by the m1login.net address or direct IP to 192.168.1.2 resulted just "time out / taking too long to respond / cannot open the page because too many redirects occurred" errors. Had to do factory reset to access the dashboard.

I tried also to change the DHCP address range to start from .50, after checking there's no devices connected with that high IPs in my wlan and then tried the data offloading connection again. Nope, still "networking error" and "ip address confect" and "configure a unique subnet."
And I see ralphstead tried changing his home router's IP too, and same problem. This seems to be a definite problem within M1 itself, with a major feature just not working at all.
Data offloading possibility to Ethernet/Wlan in addition to mobile data was my primary interest, main selling feature, so this is kind of disappointing. Any suggestions for further testing are still welcome.