add_theme_support post-thumbnails not working

Have a look at this documentation.

This feature must be called before the init hook is fired. That means it needs to be placed directly into functions.php or within a function attached to the after_setup_theme hook. For custom post types, you can also add post thumbnails using the register_post_type() function as well.

TRY this

add_theme_support( 'post-thumbnails', 
     array( 'post', 'page', 'service') 
);