Seems to me like your kppp is not configured properly. Settings for me were
Username = 3
Password = 3
But was trying without this and should work as well.
you can change the modem init strings below under modems > edit > modem > modem commands
Init string 1 = ATZ
Init string 2 = AT+CGDCONT=1,"IP"
Phone number = *99# (this gives the phone a sign to dial the default connection. You can add a different phone numbers as well for example *99***2# or *99***3# for connections 2 and 3 in the queue)
Auth = pap/chap
Let me know how this worked out for you.