LBR20 drops LTE connection and can't connect again

Hi,

My LBR20 (68N) keeps disconnecting from LTE and can't connect again. It happens with various frequency, sometimes after 1h sometimes after a week. Usually the magenta light turns on after disconnection. If I wont restart the router it will remain disconnected forever. Restarting solves the issue immediately (doesn't matter if I restart it via panel or just cut the power off). I have good LTE connection, base station is just next to my house. 

Router firmware version: V2.7.5.6

Mobile firmware version: EG18-EA-PAR01A11M4G

Do you know how to fix it? Maybe there is some workaround like to make automatic reboot once the mobile connection is lost?