I use RUT 955 in project where i collect data by JSON RPC every 60 sec. Somehow last period from 160 pieces a big quantity started to not answer to remote HTTP.
I went on the field to check, routers where power one, with LTE signal with WAN MObile active but does not transmit pockets over the wan. I made no change on MObile WAN settings, just save and router is back online again.
Some of the routers could be acces after restart with SMS comand.
I have logged to some routers by LAN and last event before recovery it was like this:
Failing rate is over 50%. ( we use SIM 1 and Main antena only)