Below are the steps which should help you connect via L2TP protocol:
1. Login to your Chrome device.
2. Click the status bar at the bottom right of your desktop.
3. Select Settings.
4. In the Internet connection section, click Add connection.
5. Select Add private network
In the Add private network dialog specify the following information:
Enter a server hostname for example for London put, lon.tigervpn.com you’ll get the complete server list in your Customer Dashboard:
Select L2TP/IPsec + Pre-shared key
tigerVPN (as same as mentioned here as tigervpn or TIGERVPN will not work)
Server CA certificate: Select Default.
User certificate: Select None installed
Username: Your tigerVPN username (the details are inside your customer Dashboard, geeks tab)
Password: Your tigerVPN password