Yes, they first told me to check with the carrier, which I did. (no blocks)
Then next step was call them when an issue is ongoing.
The problem is that this is in another country, and also that the Network cabinet is not easy reachable, it's put 3m off the ground.
Power cycling the MG re-establishes the connection. But again, not easy reachable so they just powercycle all devices that are on the main switch to the patchcabinet (modem, MX, switch,...) so not the best solution.
Just not really what we expected and want from a crazy expensive 'backup system'.
Our 60 euro Huawei dongles work better than this 600 euro + license MG.
Interestingly enough, I'm seeing this behaviour too at a client's site. MG is working for a couple of days, then has to be rebooted to be reachable again. It has worked flawlessly for roundabout a year. Fortunately, it can be rebooted easily because it's connected to a MS port but this kinda sucks.
Will possibly open up a ticket too.
Btw.: Which firmware version are you running on that MG21?