Maybe there is mistake in settings of VPN. You should have pptp severip ,username, password, check them in the computer by the first. make sure they are availiable.
I use a Hostpot Gateway with VPN on the local network (which covers all devices on that subnet,) the kids and all wireless clients are on a separate network (and subnet) called "authentication" or "public" that gives traditional internet but with an additional authentication pages like the internet mcdonalds or a library has, this is the best method I have found. If you use this method your X9S would be secured behind a VPN
