Hey Samyaza,
Thanks for writing in. That's a great question!
TCP requires WinPcap to work, and typically VPN's don't like to play nicely with WinPcap. You can read more about that in this article (specifically question 5):
https://www.winpcap.org/misc/faq.htm#Q-5You can ping using TCP on a VPN, but traceroute is a different story, because without WinPcap, PingPlotter cannot separate the hops.
You may want to try using UDP to see if that gets a response.
I hope this helps. If you need any other help with this or anything else, feel free to write us back at any time.
Cheers!
-Phillip