Not able to connect GCP windows VM telnet error .Could not open connection to the host, on port 80: Connect failed

Question

I have website hosted on GCP windows VM on IIS and running absolutely fine with internal ip address of the machine. However when trying to access the website with same internal IP through VPN it does not work . Firewall rules have been added to allow 0.0.0.0/0 TCP:80 port. when I did telnet I received following error "Could not open connection to the host, on port 80: Connect failed" Not sure what I am missing.