Did another test of connecting with the modemmanager package from comment #45. This time I clicked on "T-Mobile (Telekom) Default" and after around 1 or 2 seconds the network manager indicator icon stopped spinning. I did this a second time and the same happens. The syslog of these two attempts is attached.
Did another test of connecting with the modemmanager package from comment #45. This time I clicked on "T-Mobile (Telekom) Default" and after around 1 or 2 seconds the network manager indicator icon stopped spinning. I did this a second time and the same happens. The syslog of these two attempts is attached.