Dropdown menu does not work on mobile

Here’s what I’ve done so far to troubleshoot the problem:
– Switched to the Parent “Sela” theme (menu works fine in mobile, so not a problem with the parent theme)
– Switched back to the Child theme. Deleted everything in my child theme’s style.php file except the heading below (menu didn’t work)

/*
Theme Name: Sela Child
Description: Child theme of Sela template
Template: sela
Version: 1.0
*/

– Deleting everything except the following in my functions.php file

<?php
function my_theme_enqueue_styles() {

    $parent_style = 'sela-style';

    wp_enqueue_style( $parent_style, get_template_directory_uri() . '/style.css' );
    wp_enqueue_style( 'child-style',
        get_stylesheet_directory_uri() . '/style.css',
        array( $parent_style ),
        wp_get_theme()->get('Version')
    );
}
add_action( 'wp_enqueue_scripts', 'my_theme_enqueue_styles' );
?>

– Deactivating all my plugins (still no dropdown)

I’m at a loss what the problem could be. I’ve made major changes recently (new plugins, playing with CSS in the child theme, deleting the Jetpack plugin) and am not sure at what point the mobile menu button stopped working. Please help!