Network problem after upgrading to Kubuntu 15.04

Question

This problem started to occur after I upgraded to 15.04. I connect to Wi-Fi and after some time it disconnects. after I try to re-connect it shows following:

* Blurred areas are Wi-Fi names.

Answer 1

For me it worked by running these commands:

sudo apt-get install -d --reinstall network-manager
sudo apt-get install -d --reinstall plasma-nm

Answer 2

if that is not working try this sudo sh -c 'echo "options iwlwifi 11n_disable=1" >> /etc/modprobe.d/iwlwifi.conf' described in Unstable wireless with Intel 7260 + iwlwifi after upgrade to 15.04 or here.

Good Luck

~Kaitsh