Source: https://store-jp.nintendo.com/item/hardware-accessory/VM_CLO_S_RAAAA
Relevant part:
多くの方にご要望をいただいており、すべてのお客様にご購入いただけない状況のため、現在マイニンテンドーストアでの販売を停止しております。大変ご迷惑をおかけしております。
ただ今、近日中の抽選販売に向けて準備をしておりますのでしばらくお待ち下さい。
また、今後も順次生産を進めてまいります。
Translation:
Due to the large number of requests we have received and the fact that not all customers are able to purchase the game, we are currently suspending sales on the My Nintendo Store. We are very sorry for the inconvenience.
We are currently preparing for the forthcoming lottery sale, so please wait a while. We will also continue to progress with production in due course.
by Joseki100