Please reproduce the problem and then attach the complete file /var/log/syslog from the system. The previous JournalErrors doesn't appear to include the important data from usb-modeswitch or NetworkManager/ModemManager.
Also, lxcbr0 is not related in any way to the modem; its IP address is set up automatically, and all of it comes from lxc, a container management tool that is apparently installed on your system.
Please reproduce the problem and then attach the complete file /var/log/syslog from the system. The previous JournalErrors doesn't appear to include the important data from usb-modeswitch or NetworkManager/ ModemManager.
Also, lxcbr0 is not related in any way to the modem; its IP address is set up automatically, and all of it comes from lxc, a container management tool that is apparently installed on your system.