OpenVPN client-to-client not working on Windows clients

[giovannic]

I am running an OpenVPN server on a Debian 11 machine. I have several clients with all kind of OS (Ubuntu 20.04, Debian 11, Windows 10, iOS). However, the clients running Windows 10 are not able to ping other clients (regardless of the OS) and other clients are not able to ping Windows 10 clients. It seems like the client-to-client option is not recognized by the Windows 10 clients.

On the Windows clients I am using OpenVPN-gui (https://openvpn.net/community-downloads/ - OpenVPN-2.6.4-I001-amd64.msi)

I have already tried to add a rule to the Windows firewall to allow anything to come in or go out from port 1194.

This is the server configuration:

View OriginalServer config

port 1194
proto tcp
dev tun
ca ca.crt
cert FZ01SRVR.crt
key FZ01SRVR.key
dh dh.pem
server 10.10.10.0 255.255.255.0
client-config-dir ccd
push "redirect-gateway def1 bypass-dhcp"
push "dhcp-option DNS 208.67.222.222"
push "dhcp-option DNS 208.67.220.220"
client-to-client
keepalive 10 120
tls-auth ta.key 0
cipher AES-256-CBC
user nobody
group nogroup
persist-key
persist-tun
status openvpn-status.log
log-append openvpn.log
verb 5

This is the client configuration (cross-OS):

View OriginalWindows client config

client
dev tun
proto tcp
remote xxx.xxx.xxx.xxx 1194
resolv-retry infinite
pull-filter ignore redirect-gateway
nobind
persist-key
persist-tun
ca ca.crt
cert gestionale.crt
key gestionale.key
tls-auth ta.key 1
verb 1

What am I doing wrong?