To ensure your VPN connection works properly, you will need to go into the settings to change your remote gateway information. To do this, you will need open the FortiClient VPN and click the settings cog in the top right hand corner of the dialogue box.
After clicking the settings cog, select the "edit selected connections" option.
From here, you can go ahead and change the remote gateway to 188.8.131.52. After doing this, ensure that you click save.
After completing these three steps you will be able to successfully connect to your VPN connection.