NetworkManager applet does not detect networks

I am currently using Ubuntu Mate 16.04. When the system starts up the NetworkManager applet does not display any wireless networks. The only "solution" I currently know is to issue

sudo iwlist scan

on the command line. Afterwards NetworkManager sees the networks and I can register to my WLAN. This is quite aoying to do every time I boot the system. Is there any permanent solution for this bug?

PS: I have also confirmed with rfkill that the device is not software blocked.