'Activation of wireless network connection failed' error with a BSNL BroadBand modem# DNA-A211-I

Install wicd network manager. It should work. It's available in Ubuntu software Center.

Its all in the signal strength. The Network Manager would oscillate around -28db to 70db (meaning a large fluctuation). And with Wicked (WICD), it's around a -70 tops.

I would recommend to install EtherApe or WireShark to analyze your network connection.

sudo apt-get install wireshark

sudo apt-get install etherape