本タイトルの日本語サポートはありません。

You will receive this error when trying to play on a realm that is Full. For a better play experience, we highly recommend that you avoid realms marked as Full.

If you create a new character on a new realm and you receive the error "That name is unavailable" it means another player already has a character with that name on that realm, or this name is not allowed in WoW Classic. Customer Support cannot help with making names available in WoW Classic.