iframe domain issues leading to 500 internal server error

I have a strange issue with a website that cannot reference any resources from another site.

The source site (A) is t开发者_如何学Pythonrying to iframe a page from the other site (B). For some reason, site (B) is returning a 500 internal server error.

I then tried just to reference a simple image from site (B) with a tag and that returned a 404.

It's obviously something server related but I'm not sure what it could be. The iframe to server (B) works fine if it's used on any other site. So there is some cross-domain like issue going on when server (A) tries to contact server (B).

To make things more complicated, using "curl" from server (A) to access server (B) works fine.

Anyone encountered something like this before?

Thanks,

Andre

The 500 error could either be a circular dependency or a blacklisted server. The 404 implies the latter.

Do you control both servers? Or is B owned by someone else who might have blocked the IP of server A?

If the latter, play nicely and send the owner of server B an email. If the former, check that you've not accidentally configured apache to block any IPs.