I wan't to get rid of my tardis, because I don't like the interior, and I saw that there is a command you can transfer the ownership with. I found a player that wanted my tardis and typed in the command (tardis-ownership give 'nameofplayer'), but when I do that it says: TARDIS DOESN'T EXIST. What do I need to do?

The command is just /tardis-ownership Name

I did that, and now it says: you do not own this tardis, but I can still control it, and the person that wants it can't.