I had the same problem.
Make sure you have 128bit VPN update (live update) if it does not show up (because it has already been installed) go into the installed section (not sure exactly what it is called but the hyperlink is on the same page) re-install it as installing over modules over top can delete files (ie5 etc)
Then under DUN, SETTINGS, CONNECTIONS, SECURITY TAB make sure you have require secure connections (or something like that, the middle one)
If all other config is right this should work, worked for me
good luck
miked