It is a bug. Because it isn’t compatible with IPv6, we have filter it, but missing filter comma.

Will fix it asap, please try this.

[Interface]
Address = 192.168.12.2
PrivateKey = <private key>
ListenPort = 21841

[Peer]
PublicKey = <public key>
Endpoint = <my server>.gotdns.com:51820
AllowedIPs = 0.0.0.0/0
PersistentKeepalive = 180 # seconds