LB2120 continually rebooting

Hi

I have been using an LB2120 for a couple of years with it constantly on without any problems. Then just a couple of days ago when I tried to connect to the device using the iPhone app the power light goes orange and the reboots. If I didn’t connect to it, it continued to function as is. Then I tried connecting via the web interface. Same thing though not quite so instantly. So after a lot of playing around I decided to do a factory reset. After this I couldn’t even connect to the device . As soon as I do it just crashes. As it lost its settings it wasn’t even connected to the mobile network. I put it down to it having reached the end of its life or something. As it turns out I had a brand new one which I was going to install else where lying around. So I tried the new one. Again, connecting to it with the iPhone app crashes it . The web interface perseveres but it doesn’t save configuration and the power light flashes and then eventually goes red and reboots. So I figured the first one must not have died. I’m not sure if there was an app update recently or if the firmware updated. Could someone advise how best to proceed? As I say it was working correctly but things started going wrong when I connect via the app. For reference, I use the LB2120 in router mode which connect to a NETGEAR nighthawk WiFi router from which I connect via wired and wireless. I use an antenna and get 4 bar signal most of the time, never less than 2 bars. I’m not sure if the problem could be the WiFi router?

Thanks in advance