This article simply shows you how to resolve CORS issue when access RSS feed of wordpress from outside world.
Add below code to the end of your function.php file
add_action( 'pre_get_posts', 'add_header_origin' );
function add_header_origin() {
if (is_feed()){
header( 'Access-Control-Allow-Origin: *' );
}
} Above code will allow anyone access your RSS feed, if you need certain domains to be allowed, update * with domains, eg:
add_action( 'pre_get_posts', 'add_header_origin' );
function add_header_origin() {
if (is_feed()){
$origin = get_http_origin();
$allowed_origins = [ 'https://your.site' ];
if($origin && in_array( $origin, $allowed_origins )){
header( 'Access-Control-Allow-Origin: ' . esc_url_raw( $origin ) );
}
}
}