What is the neurological mechanism behind the "fear of failure"? Sometimes, the fear of failing at something can be debilitating, and more often than not present a barrier for that person to even try new things - the locus of the fear can be quite different between people - ranging from academic, sporting and relationships and a whole lot more.

So, my question is, what is the neurological mechanism that results in the fear of failure?
According neurological perspective,  Amygdala  is involved in pleasurable emotional learning as well as fearful emotional learning. awareness of the aversive nature of  stimuli is sufficient to guide our actions. We avoid dangerous neighborhoods
or shark-infested waters, not mainly because we have been
 attacked by sharks in those locations, but instead
because we might have been given information regarding the stimulus aversive characteristics.
Previous research did substantiate on basis of humans using fear conditioning. they had had found that the amygdala is not completely important in terms learning or developing of an external, cognitive representation of the aversive characters of a stimulus or event . 
This cognitive representation that depends on the hippocampal memory
system, which is significant in terms of developing declarative memories, which leads to recalling of past failed experience from hippocampus and feeling sense of fear of failure in future outcomes .although, the amygdala is important for expressing conditioned fear response towards the  same stimuli. 
refrence : Phelps, E., O'Connor, K., Gatenby, J., Gore, J., Grillon, C., &amp; Davis, M. (2001). Activation of the left amygdala to a cognitive representation of fear. Nature Neuroscience, 4(4), 437-441. doi: 10.1038/86110