Your relay is probably not working. From https://support.torproject.org/relay-operators/, Can I use IPv6 on my relay?:
Tor has partial support for IPv6 and we encourage every relay operator to enable IPv6 functionality in their torrc configuration files when IPv6 connectivity is available. For the time being Tor will require IPv4 addresses on relays, you can not run a Tor relay on a host with IPv6 addresses only.
You can also run VirtualBox with KVM as a backend.