If player used IPv6 to join the server, /ban-ip is invaild, /pardon-ip does run failed.

when I tried to ban a player by ban-ip ,he can login the server again.He didn't change his ipv6,and the connection between he and my server is ipv6 only.I cannot pardon his ip,too.The server returns a error that I input a wrong parameter.The following is a screenshot that I met.(The picture has some personal information,so I have to hide some parts.)