How to fix the problem of lost wifi connection?

Question

WiFi

Good afternoon, for some unknown reason, in ubuntu 14.04, the ability to connect to w-fi disappeared,
from the panel where I used to choose wi-fi - the option simply disappeared. can someone tell me what the problem is and if it is possible to solve it. before that everything worked fine, ubuntu downloaded updates, maybe after that the function disappeared

Answer 1

I had this! it just saved ctrl+alt+del i.e. log out and log in again!
but it was two times os ubuntu 16.04

Answer 2

sudo service network-manager restart
or install a new version of network manager, where, it seems, they should have fixed this bug, or stick wicd instead.