openvpn clients cannot access eachother

[mauzilla]

Out of the box setup, both clients can connect (set out a network 192.168.231.0/24):

Client A gets 192.168.231.10
Client B gets 192.168.231.11

Both can ping the gateway and access the gateway (192.168.231.1) but they have no access to eachother. I have opened rules under "openvpn" with no difference. What am I doing wrong?

[tiermutter]

Did you activate "Inter-client communication" in VPN server config?