Are you feeling glad? During last few updates, Microsoft has fixed(?) this annoying notification to a greater extend. However if you want to reproduce this error do the following:
Disable your network adaptor.
Connect your computer to another available connection (Preferably to a tethered connection)
Disconnect from the new network
Enable your default connection
Now watch the notification popping up and the network connection with “famous” yellow triangle (Warning) until next restart.