smasere on ""Not Acceptable" displays when update is clicked. WP 3.8"

Hi,

I'm trying to update a page with a YouTube embed link but it refuses to update my post.
Once I click update a blank screen pops up with the words "Not Acceptable."
This is the tag (below) that I have been using prior to updating to WORDPRESS 3.8:

[youtube id="vTQy3xumLvU"]

could it be a glitch with my theme and the new update?