Not as far as I can tell. I can connect to the same device over IPv4, and I can RDP into it over IPv6. Looking at TCPView (from Sysinternals) it doesn't look like a v6 connection is even being attempted, which ties in with the error being shown. I've restarted Windows and checked there's no rules in the firewall for it (only use the built in Windows one).
Separately, although possibly related, it's not possible to specify an IPv6 address in the server box, only DNS entries that resolve to v6 addresses