VPN tunnel is UP, but unable to ping Gateway IP

Hello Guys,

I am facing a strange issue. So, basically I have created a Site to Site VPN with my client and the issue is client is unable to reach the LAN IP from the other side to my side . So, as I was going through basic troubleshooting I noticed that I am unable to ping the gateway IP on the other side even though VPN tunnel is UP. Is it because ICMP is blocked on the other side? If so, how is the tunnel UP. Please help here.

​

Note : I'm on a Sophos Firewall.

Thanks in Advance!