The Pokémon Trainer Club and Nintendo Account login methods are not currently supported. The best way to claim your Niantic ID is to link your Pokémon GO or Pikmin Bloom account to a Google, Facebook, or Apple login. You can link an additional login method to your Pokémon GO account by following the steps in this article or link an additional login method to your Pikmin Bloom account by following this article. Once you’ve linked a Google, Facebook, or Apple login, you will be able to sign in to this website using the Google, Facebook, or Apple login provider you just linked.