Can’t embed certain youtube videos into theme

I had recently similar issue with Divi and embedding videos. At the end I realized its because oEmbed issues in WordPress sites running on host with both IPv4 and IPv6 sites.

Either you can add this code to your functions.php to fix this:

add_action( 'http_api_curl', function( $curl_handle ) {
   curl_setopt( $curl_handle, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4 );
});

Or you can download the same solution as a plugin I made – the site is in Czech Language, but it will lead to downloading very simple plugin doing the same thing