Incomprehensible "The page you were looking for doesn't exist."

Question

I am adding a comment function for each note. The specific method is to add a comment after entering the show of each note, and it will appear immediately below the same web page, as shown in the following code:

<h1>Note name<%= @note.title %></h1>
<%= @note.content %>

<%= form_with(model: @comment, url: note_comments_path(@note)) do |f| %>
  <%= f.text_area :content %>
  <%= f.submit "Add comment" %>
<% end %>

<ul>
  <% @comments.each do |c| %>
  <li>
    <%= c.content %>
  </li>
  <% end %>
</ul>

However, when I press the "Add comment" button, the browser is redirected to the "The page you were looking for doesn't exist." error message page. I can't find anything missing from the controller. Please tell me what am I missing?

This is part of NotesController

class NotesController < ApplicationController
  before_action :find_user_note, only: [:show, :edit, :update, :destroy]
  before_action :check_login!, except: [:index, :show]

  def index
    @notes = current_user.notes.includes(:user).order(id: :desc)
  end

  def new
    @note = current_user.notes.new
  end

  def create
    @note = current_user.notes.new(note_params)

    if @note.save
      redirect_to "/notes"
    else
      redirect_to "/notes/new"
    end
  end

  def show
    @note = Note.find(params[:id])
    @comment = @note.comments.new
    @comments = @note.comments.order(id: :desc)
  end
......
private
  def find_user_note
    @note = current_user.notes.find(params[:id])
  end

  def note_params
    params.require(:note).permit(:title, :content)
  end
end

This is CommentsController

class CommentsController < ApplicationController
  before_action :check_login!
  before_action :find_user_note

  def create
    @note.comments.new(comment_params)

    if @note.save
      @content = comment_params[:content]
    else
      redirect_to "/"
    end
  end

  private
  def comment_params
    params.require(:comments).permit(:content).merge(user: current_user)
  end

  def find_user_note
    @note = current_user.notes.find(params[:id])
  end

end