Slideshare links: 999 Unknown Error

Hi there,

When checking links from SlideShare recently we always get an 999 Unknown Error.

For example if you check: http://www.slideshare.net/GameManiaES/instrucciones-para-jugar-al-monopoly the response is “999 Unknown Error”; but when you try to Access the page it exists.

Can you check this, please?

https://wordpress.org/plugins/broken-link-checker/