http://nginx.org/en/....html#error_log
UPDATE: This only occurs when the signature wouldn't save (the one I wanted to post was three lines but it glitches and won't accept three lines and 1 image, so I had to make it one line and now it works).
UPDATE: Appears to have worked now although it seems your nginx isn't programmed to give error logs.
Edited by Nikolai Lubkiewicz, 24 October 2014 - 05:30 PM.