ここ読んでなかった!ダメだ〜どうしようかな
(寝なさい)
> "Fediverse usernames that begin or end with _, -, or ~, or that contain any non-alphanumeric characters, ie anything other than A-Z a-z 0-9 _ - ~, are not currently supported. Sorry. This may change in the future; follow this GitHub issue for details."