Active Admin 管理者画面からユーザー作成できない

rails g active_admin:resource user

class DeviseCreateUsers < ActiveRecord::Migration[6.0]
  def change
    create_table :users do |t|

      t.string :email,              null: false, default: ""
      t.string :encrypted_password, null: false, default: ""
      t.string   :reset_password_token
      t.datetime :reset_password_sent_at
      t.datetime :remember_created_at
      t.timestamps null: false
    end
    add_index :users, :email,                unique: true
    add_index :users, :reset_password_token, unique: true  
  end
end

ActiveAdmin.register User do
  permit_params :email, :reset_password_token, :reset_password_sent_at, :remember_created_at
end

ActiveAdmin.register User do
  permit_params :email, :password, :password_confirmation

  index do
    selectable_column
    id_column
    column :email
    column :current_sign_in_at
    column :sign_in_count
    column :created_at
    actions
  end

  filter :email
  filter :current_sign_in_at
  filter :sign_in_count
  filter :created_at

  form do |f|
    f.inputs do
      f.input :email
      f.input :password
      f.input :password_confirmation
    end
    f.actions
  end
end