也许你能帮助我。我的机器运行的是 Ubuntu 14.04 64 位，我创建了新的 Cisco VPN 配置文件，输入了网关、用户名和密码，但尝试连接时出现错误：
日志输出：
Oct 16 18:12:57 HP-Workstation NetworkManager[801]: Starting VPN service 'vpnc'...
Oct 16 18:12:57 HP-Workstation NetworkManager[801]: VPN service 'vpnc' started (org.freedesktop.NetworkManager.vpnc), PID 3136
Oct 16 18:12:57 HP-Workstation NetworkManager[801]: VPN service 'vpnc' appeared; activating connections
Oct 16 18:12:57 HP-Workstation NetworkManager[801]: VPN plugin state changed: starting (3)
Oct 16 18:12:57 HP-Workstation NetworkManager[801]: VPN connection 'IT Academy' (Connect) reply received.
Oct 16 18:12:57 HP-Workstation NetworkManager[801]: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/tun0, iface: tun0)
Oct 16 18:12:57 HP-Workstation NetworkManager[801]: SCPlugin-Ifupdown: device added (path: /sys/devices/virtual/net/tun0, iface: tun0): no ifupdown configuration found.
Oct 16 18:12:57 HP-Workstation NetworkManager[801]: /sys/devices/virtual/net/tun0: couldn't determine device driver; ignoring...
Oct 16 18:12:57 HP-Workstation ModemManager[652]: Modem /org/freedesktop/ModemManager1/Modem/0: access technology changed (umts -> hsupa)
Oct 16 18:12:58 HP-Workstation ModemManager[652]: Modem /org/freedesktop/ModemManager1/Modem/0: access technology changed (hsupa -> hspa)
Oct 16 18:12:58 HP-Workstation ModemManager[652]: Modem /org/freedesktop/ModemManager1/Modem/0: signal quality updated (77)
Oct 16 18:12:58 HP-Workstation NetworkManager[801]: SCPlugin-Ifupdown: devices removed (path: /sys/devices/virtual/net/tun0, iface: tun0)
Oct 16 18:12:58 HP-Workstation NetworkManager[801]: VPN plugin failed: 1
Oct 16 18:12:58 HP-Workstation NetworkManager[801]: VPN plugin state changed: stopped (6)
Oct 16 18:12:58 HP-Workstation NetworkManager[801]: VPN plugin state change reason: 0
Oct 16 18:12:58 HP-Workstation NetworkManager[801]: Policy set 'Play Online Default' (ppp0) as default for IPv4 routing and DNS.
Oct 16 18:12:58 HP-Workstation NetworkManager[801]: error disconnecting VPN: Could not process the request because no VPN connection was active.
Oct 16 18:13:01 HP-Workstation ModemManager[652]: Modem /org/freedesktop/ModemManager1/Modem/0: signal quality updated (90)知道什么可能导致此问题吗？