Das nervt mich schon seit irgendeiner LM 18 Version => plötzlich kam immer die Meldung Netzwerkverbindung fehlgeschlagen, obwohl man problemlos im WLAN unterwegs war. Problem war nicht leicht im Netz zu finden. Es lag wohl im LTE Modem…

https://askubuntu.com/questions/1115083/connection-failed-activation-of-network-failed-error

Step #4, above, showed us that there is in fact a cdc_ether kernel module installed. This may be due to a previous USB to 4G dongle, a USB to Ethernet dongle, a TomTom GPS device, or an internal 4G adapter.

Since we’re not sure exactly which software install might have added this cdc_ether driver, and associated software, we’ll try a safe way to fix this first…

Create a new blacklist file…

In terminal

sudo -H vi /etc/modprobe.d/blacklist-cdc_ether.conf # create the file

Add these two lines…

blacklist cdc_ether

blacklist usbnetgeditblacklist usbnet

Save the file and reboot the computer.

Then do…

sudo lshw -C network # show us the current network devices

and confirm that the enp0s20f0u3c2 ethernet device is no longer present. If it’s still there, then do the following, but only if it’s still there…

sudo modprobe -r cdc_ether usbnet # remove these kernel modules

sudo update-initramfs -c -k "$(uname -r)" # update the initramfs

reboot the computer and check the lshw command again.

Das hat es dann hoffentlich erledigt.