User with nested attributes , error on password problem

gistfile1.haml

= simple_form_for [:admin, @user], remote: true, html: { novalidate: 'true'} do |f|
  .tab-content
    #basic.tab-pane.active
      = f.input :login
      = f.simple_fields_for :password_attributes do |pass|
        = pass.input :password, label: 'Hasło'
        = pass.input :password_confirmation, label: "Potwierdzenie hasła"
        = pass.input :user_id, as: :hidden, input_html: {value:  @user.id }, wrapper: :default
    #personal.tab-pane
      = f.simple_fields_for (@user.persisted? ? :personal : :personal_attributes), @user.personal do |p|
        = p.input :pesel