Why is my Bootstrap 5 navbar not displaying the drop down menu on smaller screens?

I am trying to develop a bootstrap 5 theme for the latest WordPress. I am using Navwalker from here: https://github.com/wp-bootstrap/wp-bootstrap-navwalker. My bootstrap Navbar does not dropdown on smaller screens.

Is it not working because I am using Bootstrap 5 and not bootstrap 4?

Here is my code from my header.php file:

<nav class="navbar navbar-expand-md navbar-dark bg-dark" role="navigation">
    <div class="container">
        <!-- Brand and toggle get grouped for better mobile display -->
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-controls="bs-example-navbar-collapse-1" aria-expanded="false" aria-label="<?php esc_attr_e( 'Toggle navigation', 'your-theme-slug' ); ?>">
            <span class="navbar-toggler-icon"></span>
        </button>
        <a class="navbar-brand" href="#">Navbar</a>
        <?php
        wp_nav_menu( array(
            'theme_location'    => 'primary',
            'depth'             => 2,
            'container'         => 'div',
            'container_class'   => 'collapse navbar-collapse',
            'container_id'      => 'bs-example-navbar-collapse-1',
            'menu_class'        => 'nav navbar-nav',
            'fallback_cb'       => 'WP_Bootstrap_Navwalker::fallback',
            'walker'            => new WP_Bootstrap_Navwalker(),
        ) );
        ?>
    </div>

</nav>

Here is my code from my functions.php file:

function register_navwalker(){
require_once get_template_directory() . '/class-wp-bootstrap-navwalker.php';
}
add_action( 'after_setup_theme', 'register_navwalker' );

/*Navigation Menus*/
register_nav_menus( array(
    'primary' => __( 'Primary Menu', 'bootstrap' ),
    'secondary' => __( 'Secondary Menu', 'bootstrap' )
) );

        

This is my error:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘register_navwalker’ not found or invalid function name in C:UsersapiroLocal Siteswordpressbootstrapthemeapppublicwp-includesclass-wp-hook.php on line 292

Call Stack

Time    Memory  Function    Location

1 0.0003 413560 {main}( ) …index.php:0

2 0.0006 413832 require( ‘C:UsersapiroLocal Siteswordpressbootstrapthemeapppublicwp-blog-header.php’ ) …index.php:17

3 0.0006 414376 require_once( ‘C:UsersapiroLocal Siteswordpressbootstrapthemeapppublicwp-load.php’ ) …wp-blog-header.php:13

4 0.0007 414816 require_once( ‘C:UsersapiroLocal Siteswordpressbootstrapthemeapppublicwp-config.php’ ) …wp-load.php:37

5 0.0007 419496 require_once( ‘C:UsersapiroLocal Siteswordpressbootstrapthemeapppublicwp-settings.php’ ) …wp-config.php:79

6 0.0325 2624792 do_action( ) …wp-settings.php:538

7 0.0325 2625168 WP_Hook->do_action( ) …plugin.php:484

8 0.0325 2625168 WP_Hook->apply_filters( ) …class-wp-hook.php:316