I can't connect to VPN service via pptp

I am running openSUSE Leap 42.1.

Linux sayHi 4.1.21-14-default #1 SMP PREEMPT Sun Apr 17 07:27:45 UTC 2016 (fc187c1) x86
_64 x86_64 x86_64 GNU/Linux

When I try to connect to VPN via PPTP, it just faild.
Here are the details :

NetworkManager[962]: <info>  VPN service 'pptp' disappeared

I found this in “journalctl”

Authentication issue perhaps? Open a terminal window and do

sudo journalctl -f

then try activating the VPN connection. Look for authentication issues during the connection process.

You could also try recreating the NM VPN connection, just in case the existing configuration is not quite right for some reason. Not sure what else to advise as my usual VPN connection is working as it always has.