RSS Feeds from same parent domain not loading

This may get fixed in WP 3.6

Until then, there is an UGLY and POTENTIALLY UNSAFE change you can make to allow your server to access remote RSS feeds:

edit [moderated – do not edit core WordPress files]

on line 72, find the following:
'reject_unsafe_urls' => true,

change it to:
'reject_unsafe_urls' => false,

This is still not properly fixed in 3.6 — this latest release solves the problem for multisite blogs accessing another sub-site, but not separate WP installations, or RSS feeds from other hosts on the LAN whose external IP differs from the internal IP.

MODERATOR: do not edit until there is a viable fix. We who modify core WP files know that this is a potentially unsafe and unstable solution, but until there is a viable workaround, this is the only means by which we may include certain feeds.

There is an UGLY and POTENTIALLY UNSAFE change you can make to allow your server to access remote RSS feeds

In WP 3.5:
(1) edit wp-includes / functions.php
(2) find 'reject_unsafe_urls' => true,
(3) change it to 'reject_unsafe_urls' => false,

In WP 3.6:
(1) edit wp-includes / http.php
(2) find function wp_safe_remote_request
(3) remove (or comment out) the line $args['reject_unsafe_urls'] = true;

BE AWARE that this will make your site VULNERABLE: if any of the sites you draw dynamic data from get spoofed, you could end up including rogue content in your site. Be EXTREMELY careful which URLs you use to include dynamic content.

Try add this in your functions.php file:

function http_request_local( $args ) {
   $args['reject_unsafe_urls'] = false;
   return $args;
}
add_filter( 'http_request_args', 'http_request_local' );