Coding return error that doesn't make sense

<?php

function my_plugin_menu() {

    // Page Title: My Plugin Settings Page
    // Menu Title: My Plugin
    // Slug: Same as menu name, but with hyphens instead of spaces
    // Make sure user has ability to manage plugin options
    // my_plugin_options_page() is the function for what displays on the options page

  /*use add_options_page function
  * add_options_page($page_title, $menu_title, $capability, $menu_slug, $function)

  */

    add_options_page(
    'My Plugin Settings Page',
    'My Plugin',
    'manage_options',
    'my-plugin',
    'my_plugin_options_page'
    );


}
add_action('admin_menu', 'my_plugin_menu');

function my_plugin_options_page(){
  if(! current_user_can('manage_options')){
    wp_die("you do not have sufficient permissions to access this page.");  

  }

  echo "<p>Welcome to our plugin page!<.p>";
}


?>