1- From Start Menu click on Run or from keyboard click on Windows key with R key. Write "regedit" and click on OK.
2- After Registery Editor opened, expand on the breakdown below.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\RasMan\Parameters
3- In free field Right Click with Mouse and choose New then DWORD (32 - bit) Value.
4-Give ProhibitIpSec name to the composed DWORD.
( Be careful about the upper and lower case.)
5-Right Click on ProhibitIpSec'e and choose Modify.
6-Write 1 in Value data part and click on OK.