I am trying to connect to a VPN via L2TP over IPsec in Ubuntu 16.04. I know a small handful of posts here and bug reports have begun to document this issue, but I believe my experience, if somewhat naive, may add to the discussion, and perhaps I am overlooking something that may make it work for me.
First, I followed the instructions here to successfully install network-manager-l2tp: https://github.com/nm-l2tp/network-manager-l2tp
The L2TP option then appeared for the first time in my Add a Connection Type dropdown.
I started a new L2TP connection and entered the IP address, my user name, and my password.
Then I clicked on "IPsec Settings" and entered my shared secret.
When I try to connect to the VPN, I get the error in the upper right corner of the screen "VPN Connection Failed: The VPN connection failed because there were no valid VPN secrets."
I also tried the instructions here, and got the same error: https://github.com/nm-l2tp/network-manager-l2tp/issues/12
I have tried restarting, etc. I do not know what this error means. Thoughts?