Getting "cannot convert nil to param" error from Phauxth registration

Hi!

I have a problem after modifying the standard registration flow from Phauxth. I have generated the auth with Phauxth and modified it to add first_name, last_name and password confirmation and changed the route scope to /admin. The registration works fine if all fields are provided, but if there is a validation error, it fails with the following message:

ArgumentError at POST /admin/users
cannot convert nil to param

The code looks like this:

Form:

<%= form_for @changeset, user_path(@conn, :create), fn f -> %>
<%= if @changeset.action do %>
  <div class="alert alert-danger">
    <p>Please check the errors below.</p>
  </div>
<% end %>

  <div class="form-group">
    <%= text_input f, :first_name %>
    <%= error_tag f, :first_name %>
  </div>

  <div class="form-group">
    <%= text_input f, :last_name %>
    <%= error_tag f, :last_name %>
  </div>

  <div class="form-group">
    <%= email_input f, :email %>
    <%= error_tag f, :email %>
  </div>

  <div class="form-group">
    <%= password_input f, :password %>
    <%= error_tag f, :password %>
  </div>

  <div class="form-group">
    <%= password_input f, :password_confirmation %>
    <%= error_tag f, :password_confirmation %>
  </div>

    <%= submit "Register" %>
<% end %>

user_controller.ex

  def create(conn, %{"user" => %{"email" => email} = user_params}) do
    key = Phauxth.Token.sign(conn, %{"email" => email})

    case Accounts.create_user(user_params) do
      {:ok, user} ->
        Log.info(%Log{user: user.id, message: "user created"})
        Accounts.Message.confirm_request(email, key)
        success(conn, "User created successfully", session_path(conn, :new))

      {:error, %Ecto.Changeset{} = changeset} ->
        render(conn, "new.html", changeset: changeset)
    end
  end

accounts.ex

  def create_user(attrs) do
    %User{}
    |> User.create_changeset(attrs)
    |> Repo.insert()
  end

user.ex

  def create_changeset(%User{} = user, attrs) do
    user
    |> cast(attrs, [:first_name, :last_name, :email, :password])
    |> validate_required([:first_name, :last_name, :email, :password])
    |> unique_email
    |> validate_confirmation(:password)
    |> validate_password(:password)
    |> put_pass_hash
  end

router.ex

  scope "/admin", MyApp do
    resources "/users", Admin.UserController
  end

If I inspect the changeset it looks like this:

#Ecto.Changeset<
  action: :insert,
  changes: %{
    email: "email@gmail.com",
    last_name: "last name",
    password: "password"
  },
  errors: [
    password_confirmation: {"does not match confirmation",
     [validation: :confirmation]},
    first_name: {"can't be blank", [validation: :required]}
  ],
  data: #MyApp.Accounts.User<>,
  valid?: false

image1230×950 68.3 KB

Appreciate any help with this.