Render JSON view using render_one, template not found error

How do I render json using Phoenix.View.render_one? because when I try to render a json view, it result to template not found error. Phoenix tries to render an html instead.

AnnotationView

defmodule RumblWeb.AnnotationView do
  use RumblWeb, :view

  def render("annotation.json", %{annotation: annotation}) do
    %{
      id: annotation.id,
      body: annotation.body,
      at: annotation.at,
      user: render_one(annotation.user, RumblWeb.UserSessionView, "user.json")
    }
  end
end

UserSessionView

defmodule RumblWeb.UserSessionView do
  use RumblWeb, :view

  def render("user.json", %{user: user}) do
    %{id: user.id, name: user.name}
  end
end

I use the annotation view, when a user joins a channel:

    annotations =
      video
      |> Multimedia.list_annotations()
      |> Phoenix.View.render_many(AnnotationView, "annotation.json")

Here’s the exception:

[error] an exception was raised:
    ** (Phoenix.Template.UndefinedError) Could not render "user.json" for RumblWeb.UserSessionView, please define a matching clause for render/2 or define a template at "lib/rumbl_web/templates/user_session/*". The following templates were compiled:

* new.html

Assigns:

%{user_session: #Rumbl.Accounts.User<__meta__: #Ecto.Schema.Metadata<:loaded, "users">, confirmed_at: nil, email: "nulloverridedota2@gmail.com", hashed_password: "$2b$12$ugeqoWBcSJO65ZNemMggruOgSqcyA.pvlOJemo0VGTvFWMa19cCuK", id: 2, inserted_at: ~N[2020-05-01 09:23:06], name: "Jhefrey", updated_at: ~N[2020-05-01 09:23:06], videos: #Ecto.Association.NotLoaded<association :videos is not loaded>, ...>, view_module: RumblWeb.UserSessionView, view_template: "user.json"}

Assigned keys: [:user_session, :view_module, :view_template]

If the information is not enough, I will provide more.

Thank you.

render_one(annotation.user, RumblWeb.UserSessionView, "user.json", as: :user)
or
def render("user.json", %{user_session: user}) do