Battle Info: the reason why Lucy's Urano Metria (or Ultimate Magic of the Stars) did not work was because Obra (and his little brown demon thing) from Raven Tail used his magic to nullify Lucy's magic.
Several people noticed this however nothing was done about this (maybe due to the lack of evidence or a reason unknown to us)

Anime: Fairy tail

Episodes Used: Episode 159

Song: Fallen Angels - Black Veil Brides

DISCLAIMER: I do not own, nor do I claim ownership over, the footage or music used in this video. This video is purely fan made.