Ubuntu 16.04 LTS Network Manager cannot add VPN - greyed out

In case anyone else has this issue, the wording "Add A VPN Connection" is super misleading as it's telling you that you need to add a VPN connection, not that you are supposed to click to add one from there.

So select Edit Connections, Add, and then select your VPN from there.

I recently set up VPN on Xubuntu 16.04 LTS for the first time. This is what I had to do:

sudo apt install openvpn
sudo apt install network-manager-openvpn-gnome 

I used network-manager-openvpn-gnome instead of network-manager-openvpn to get the option to import the VPN configuration files.

After that I could go to:

1. Edit Connections at the bottom of the menu
2. Click on the Add button on the next window
3. Choose Connection type
4. Import a saved VPN configuration

After that I was able to edit the VPN connection by

1. Edit Connections... at the bottom of the menu
2. Select the VPN connection I want to edit
3. Click on the Edit button

The easy way is using a command on terminal:

nm-connection-editor

nm-applet normally starts at login by the desktop session manager and does not need to be run manually.

In some versions of Ubuntu there were problems in the security policy.

To solve this you should edit the file 'org.freedesktop.NetworkManager.policy' on /usr/share/polkit-1/actions/

sudo -H gedit /usr/share/polkit-1/actions/org.freedesktop.NetworkManager.policy

And change this action:

<action id="org.freedesktop.NetworkManager.settings.modify.own">
.
.
.
<allow_inactive>no</allow_inactive>

to

<allow_inactive>yes</allow_inactive>

Then restart network-manager

sudo systemctl restart network-manager