img src not working correctly in custom post type

Add this following function to your functions.php of your theme or child theme.

function homeURLshortcode()
{
    return home_url();
}
add_shortcode('homeurl', 'homeURLshortcode');

This will create a shortcode like [homeurl] which you can use to add in any visual editor and it will render as your main domain address, like http://domain.com.

So for your image url you need to add [homeurl]/wp-content/uploads/2018/05/video-popup.png