Hello Mickey,
I have tested this code in my local testing server and there are no issues with it:
// Add custom banner with shortcode
// =============================================================================
function add_shortcode_banner(){
echo do_shortcode('[your shortcode here]');
}
add_action('x_before_view_global__slider-below', 'add_shortcode_banner');
add_action('x_after_masthead_end', 'add_shortcode_banner');
// =============================================================================
You might be having a file permission or upload timeout in your server. You may need to login to your FTP, browse to wp-content/themes/pro-child/. Edit the functions.php file in that folder and insert the code above.
Please let us know if this works out for you.