pptp VPN по WiFi не работает

Я запускаю Ubuntu 14.04, и я пытаюсь настроить pptp VPN между мной и сервером. Я использую network-manager для этого.

Теперь, VPN работает отлично, когда я нахожусь на Ethernet, тогда как на WiFi мой ноутбук не знает, как достигнуть сервера (даже при том, что ping работы как exepected):

15:50:35  NetworkManager[16692]: <info> Starting VPN service 'pptp'...
15:50:35  NetworkManager[16692]: <info> VPN service 'pptp' started (org.freedesktop.NetworkManager.pptp), PID 28057
15:50:35  NetworkManager[16692]: <info> VPN service 'pptp' appeared; activating connections
15:50:35  NetworkManager[16692]: <info> VPN plugin state changed: starting (3)
15:50:40  NetworkManager[16692]: <info> VPN connection 'pacage' (Connect) reply received.
15:50:40  pppd[28069]: Plugin /usr/lib/pppd/2.4.5/nm-pptp-pppd-plugin.so loaded.
15:50:40  pppd[28069]: pppd 2.4.5 started by root, uid 0
15:50:40  pppd[28069]: Using interface ppp0
15:50:40  pppd[28069]: Connect: ppp0 <--> /dev/pts/23
15:50:40  NetworkManager[16692]:    SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
15:50:40  NetworkManager[16692]:    SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/ppp0, iface: ppp0): no ifupdown configuration found.
15:50:40  NetworkManager[16692]: <warn> /sys/devices/virtual/net/ppp0: couldn't determine device driver; ignoring...
15:50:40  pptp[28073]: nm-pptp-service-28057 log[main:pptp.c:314]: The synchronous pptp option is NOT activated
15:50:40  pptp[28075]: nm-pptp-service-28057 warn[open_inetsock:pptp_callmgr.c:329]: connect: No route to host
15:50:40  pptp[28075]: nm-pptp-service-28057 fatal[callmgr_main:pptp_callmgr.c:127]: Could not open control connection to x.x.x.x
15:50:40  pptp[28073]: nm-pptp-service-28057 fatal[open_callmgr:pptp.c:487]: Call manager exited with error 256
15:50:40  pppd[28069]: Modem hangup
15:50:40  pppd[28069]: Connection terminated.
15:50:40  NetworkManager[16692]:    SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/ppp0, iface: ppp0)
15:50:40  NetworkManager[16692]: <warn> VPN plugin failed: 1
15:50:40  pppd[28069]: Exit.

Что я пропускаю здесь?