When this has happened to me before it usually means the video can't be played on a mobile device like a phone. It should play on a desktop or laptop. Hope this helps 
@TeamYouTube Why can't I play any videos on my phone? Get this comin up each time. Tried Wi-Fi and 4g. Was fine ydaypic.twitter.com/Bb1MYGenJ5
-
-
Thanks. Twitter will use this to make your timeline better. UndoUndo
-
Loading seems to be taking a while.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.