After rebooting, NetworkManager all of the sudden has stopped working. Its icon appeared in the tray, then disappeared, then appeared again and so on 3-4 times.
All my config files are correct, I simply haven't changed anything.
I found this https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1489154
However, it seems overcomplicated.
I have internet connection now, though, via wpa_supplicant.
So what do I do to fix it?
Is that your bug ? If so read the bug report
The really mean comment #7 which give a detailed description of why this is "not a bug" and what to do to resolve the problem.
and later ...
so, run
If that does not fix your problem or that is not your bug you are barking up the wrong tree and we need more information.