eriku

Maybe you can try this alternative to solve your problem.
No shortcode is needed to embed your url, and it’s absolutely working for me. Sometimes, the problem is not in your functions, it’s only hosters who don’t allow external urls to be embed by default settings
on your hosting plans.
Thanks for the feedback if it solves your problem.

// Enable oEmbed on a specific element

add_filter( 'the_content', array( $wp_embed, 'run_shortcode' ), 8 );
add_filter( 'the_content', array( $wp_embed, 'autoembed'), 8 );