Vpn connection Failure

[mghorobei]

Hi
I'm new in Linux, I create and configured Vpn pptp based on the commands that i found in linux forms.
then when i want to start to connect via vpn pptp, I got this error "" VPN connection failure ..."
what should i do ? please help me
this is my log file reported:

May 22 12:24:13 dhcp7 pppd[5808]: Plugin nm-pppd-plugin.so loaded.
May 22 12:24:13 dhcp7 pppd[5808]: nm-pppd-plugin: plugin initialized.
May 22 12:24:13 dhcp7 pppd[5808]: nm-pppd-plugin: CHAP check hook.
May 22 12:24:13 dhcp7 pppd[5810]: pppd 2.4.4 started by root, uid 0
May 22 12:24:13 dhcp7 pppd[5810]: Using interface ppp0
May 22 12:24:13 dhcp7 pppd[5810]: Connect: ppp0 <--> /dev/pts/1
May 22 12:24:14 dhcp7 pppd[5810]: nm-pppd-plugin: CHAP check hook.
May 22 12:24:14 dhcp7 pppd[5810]: nm-pppd-plugin: CHAP check hook.
May 22 12:24:23 dhcp7 pppd[5810]: Terminating on signal 15
May 22 12:24:23 dhcp7 pppd[5810]: Child process /usr/sbin/pptp 173.212.240.155 --nolaunchpppd (pid 5811) terminated with signal 15
May 22 12:24:23 dhcp7 pppd[5810]: Modem hangup
May 22 12:24:23 dhcp7 pppd[5810]: Connection terminated.
May 22 12:24:23 dhcp7 pppd[5810]: Exit.
thanks

[BrianMicek]

Hi mghorobei,
does this help?

http://ubuntuforums.org/archive/index.php/t-382408.html

[mghorobei]

Hi
I done ur suggestion but i couldn't solve my problem