Hi Mihaela,
That warning message means the cellular communication in you panel isn’t reliably reaching Alarm.com. I checked and currently there isn’t a known issue with Verizon in your area. Are you familiar with the 3G cellular sunset?
I suspect that Verizon has recently reduced 3G capacity in your area as part of the sunset and it’s making it harder for your panel to communicate. I sent a message to your panel and it took almost a half hour to respond. It should have only been seconds.
Assuming 3G support in your area is the problem here, the solution is to upgrade the cellular communication module from 3G to 4G. You can order a 4G module here.
I’ll attempt to update your panel firmware to the latest to prepare for this. Finally, when a warning does occur, you can acknowledge it like this to make it go away. But since the actual cellular communication problem isn’t resolved yet I think it will come back.