[lubuntu] Can't coect Usb modem on Lubuntu 16.04

My usb modem is detecting in network manager, however on clicking coect button, it keeps on going for few minutes and discoects thereafter.
Please see output of various queries below-

lsusb:
Bus 002 Device 011: ID 12d1:1506 Huawei Technologies Co.,Ltd. Modem/Networkcard

wvdial:

WvDial: Inteet dialer version 1.61
Caot open /dev/ttyUSB0: Device or resource busy
Caot open /dev/ttyUSB0: Device or resource busy
Caot open /dev/ttyUSB0: Device or resource busy

I also tried to install drivers as suggested in many forums, and modeswitch but with no joy. Please see output of

sudo usb_modeswitch -v 0x12d1 -p 0x1506 -M "5553424312345678000000000000001106200000010000000 0000000000000"
Look for default devices ...
product ID matched
Found devices in default mode (1)
Access device 003 on bus 002
Current configuration number is 1
Use interface number 0
Use endpoints 0x02 (out) and 0x82 (in)
Error: can't use storage command in MessageContent with interface 0;
interface class is 255, expected 8. Abort

Please suggest what I might be missing here.
Regards,