I have a Huawei me906e broadband modem (in a M.2 to USB adapter). In this modem I inserted a SIM card which I previously tested in my phone and it works fine. After several obstacles I managed to have this modem properly detected by networkmanager. I created a connection with default settings and it does connect:
As you see I have an IP address, it also detects two DNS servers. Now the problem is that it just doesn't work at all. If I open Network Tools from GNOME, I can see that the transmission and reception errors counters are going up constantly, all other counters are at zero all the time.
If I disable my regular ETH connection (so that this modem connection would be the only one available), I can ping only "myself" - trying to ping any of the two DNS servers or the 18.104.22.168 results in 100% packet loss.
This is actually the first time I try to use a broadband modem on a PC, so I just have no idea where to go from here.
EDIT: I've managed to get this working on Windows 7 running inside a Virtual Box, so the modem and the SIM card are both functional.