This is likely to either be that you have filtering on your internet connection, or that there is something unusual about the video that our video player isn't handling correctly.
If it is something to do with your internet connection, other Auras should fail to work too. Please try some Auras on this page : http://www.aurasma.com/auras.jsp
and let us know whether they work.
It would be useful if you could give me a share link to the aura with the video, or alternatively you can identify it through giving your dev studio username, and the overlay / aura name. Either post here or email to email@example.com
Also can you say what phone/tablet you are running the app on?