GL-AXT1800 + GL-M2 (RM520N-GL): Lose internet access

Routers
3

I have also applied this fix - Spitz x3000 - potential bug in modem.sh check_ip() to the GL-AXT1800.

By changing 0.0.0.0 to "0.0.0.0", but it did not help because AT+CGPADDR command did not return any 0.0.0.0 IP address.