Highlighted image of Wordpress does not appear in Admin

Question

I configured in my functions.php the code that enables the Post Thumbnails theme, but does not appear in wp-admin.

<?php
add_theme_support( 'post-thumbnails' );
set_post_thumbnail_size( 1280, 720 );

When I create a post, there is no option to upload the highlighted image. So I’ve done the following procedures to try to understand what’s going on.

1. I disabled all plugins
2. I changed theme (and the highlighted image appears)
3. I removed all the functions code, leaving only the code above
4. I updated the Wordpress

I don’t know what to do anymore, I’ve done a lot of research and I can’t find a solution. Could someone have mercy on this soul? Thank you!!!

Answer 1

You used the hook after_setup_theme to add thumbnails support?

function theme_setup(){

    /** post thumbnail **/
    add_theme_support( 'post-thumbnails' );

}
add_action( 'after_setup_theme', 'theme_setup' );