IPFire on Hetzner cloud: unable to establish connections between the machines on the internal network

Hi,

I have setup IPFire on the Hetzner cloud as described here.

The VPN connection and firewall are functioning as expected; however, we are unable to establish connections between the machines on the internal network. Attempting to ping machine 10.0.0.3 from machine 10.0.0.7 produces the following output:

ping 10.0.0.3
PING 10.0.0.3 (10.0.0.3) 56(84) bytes of data.
From 10.0.0.7 icmp_seq=1 Destination Host Unreachable

As recommended by the guide, the traffic should be routed through the default gateway, which is 10.0.0.1. This can be confirmed by running netstat -rn on machine 10.0.0.7:

Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
0.0.0.0         10.0.0.1        0.0.0.0         UG        0 0          0 ens10
10.0.0.0        0.0.0.0         255.255.0.0     U         0 0          0 ens10
172.17.0.0      0.0.0.0         255.255.0.0     U         0 0          0 docker0
172.18.0.0      0.0.0.0         255.255.0.0     U         0 0          0 br-9e91e730653a

The “Static Routes for GREEN” have also been set up in IPFire. Given these settings, what is blocking internal communications?