Ubuntu – Network connection not prompting for password

I'm looking at my syslog and seeing very little in the way of useful information about this, but whenever I try to connect to a wifi or VPN connection, I don't get any prompt for auth but the menu on Gnome says "waiting for authentication". I'm not sure how to go about fixing this? It seems to have started happening only since I upgraded to 16.04, and I'm using vpnc (Cisco VPN) on top of the Network-Manager thing.

The syslog just contains info like the UI, e.g it shows the states going from waiting for authorisation to disconnected, it doesn't say anything about trying to prompt for auth.

So far I've tried:

• Re-installing the network-manager
• Restarting dbus
• Multiple reboots
• Cleaning out the folder with all the network configurations in and starting "from scratch"

These steps were taken from the answers in: Unable to connect to VPN using gnome-network-manager

Which this may be a duplicate of? I'll let this exist for now as the solutions there didn't help me and I'm not sure the root cause is the same.

It happens for WiFi, VPN, and any other type of connection which requires auth and uses the network-manager application.

kern.log contains:

May 16 10:11:58 joshuagdev NetworkManager[820]: <error> [1463389918.6751] vpn-connection[0x18b7400,c69258b7-65c1-41d2-86a0-7270b1d4e2a7,"Cambridge VPN",0]: Failed to request VPN secrets #3: No agents were available for this request.

I'm not sure exactly what this means, but it looks like it could be the root cause.

Update. I've managed to connect to the VPN using a terminal:

root@host:/home/user# vpnc-connect
Enter IPSec gateway address: hostname
Enter IPSec ID for hostname: groupuser
Enter IPSec secret for groupuser@hostname: secret
Enter username for hostname: user
Enter password for user@hostname: rsapassword
VPNC started in background (pid: 10735)...

While this solves the problem that I can't get on the VPN, it doesn't solve the problem that I now have to do it the hard way. More suggestions are always welcome!