I'm running 16.04 with Ethernet connection set to automatically connect to my VPN at start up in Network Manager (NM).
However, the NM password window appears at the Ubuntu login screen asking for the VPN password and blocks entering my Ubuntu password. After cancelling the NM window 3 times it goes away and I login to Ubuntu with my user password. I then have to select the Ethernet connection from NM in the system tray and connection proceeds without having to enter the VPN password (because the gnome2 key ring has the VPN connection password).
I would like to be able login to Ubuntu without interference from NM and have NM automatically connect to the VPN.