WiFi Connection password issue

Ubuntu Mate 15.10 on a Dell Inspiron 3050. I just completed the install and connected to my WiFi thusly:

“Connect to hidden network” and provided the name and password (WPA & WPA2 Personal security). I “Store password for all users” and edited the connection to [X] Automatically connect… and [X] All users may connect. And I can connect.

In theory this will allow WiFi to connect before a user logs in. However, that does not seem to work with the latest versions of Ubuntu so I also added “auto wlp2s0” to /etc/network/interfaces. wlp2s0 being the name of the wireless interface as shown by ifconfig. Still does not work but that was not my final design. I planned to have an automatic logon by a low privileged userid which would be used simply to play video from the PC to a large screen TV.

I created the user and pared down the permissions to [X] Connect to wireless and ethernet networks; [X] Use audio devices and [X] Use video devices. I added the necessary lines to /etc/lightdm/lightdm.conf to establish the autologon:

[SeatDefaults]
autologin-user=movies

The autologon works. However, the system prompts the user for the Wifi password even though I had already saved it “For all users.” While logged on as user movies I entered the WiFi password, saved it (tried both for This user only and All users) rebooted and was prompted for the WiFi password again each time.

Thinking that this might be a permissions issue I created a second administrator account. Same game. I am prompted for the WiFi password each time when the new administrator logs on. My original account is the only one which will automatically connect to WiFi upon logon.

I have another PC running Ubuntu Mate 15.04 configured much the same way. The low privileged user automatically logs on and WiFi automatically connects. I have compared settings between the PCs and can find nothing which would seem to be different.

Any ideas?

TIA,

Ken