Select the MAIN Routing Table. The interface corresponding to your tunnel. In the destination address, you specify the address of the device to which you are sending the ping, then specify the netmask. And the gateway through which you want to send traffic, in this case the IP address of Vigor. These settings can be applied to all devices.
Also, as a check, try to ping not by the usual command, but by the following:
ping -I <source IP> <destination IP>