Having strange result on probability density function

I found out there was some difficulty while my project is going on. Hopefully request for consultation in order to complete my final year project and pass for my degree.

With the attachment below, there will be showing my result that had been generated by Easyfit software. As the graph show, the distribution density function for Generalized Pareto distribution were not fitting the histogram and provided with a horizontal line which is a terrible run off from the histogram parameter. However, this situation didn’t prevent it to be the 1st rank in the goodness of fit test.

[John D'Errico]

It looks like you have a uniform distribution. So why are you trying to fit a variety of other distributinos that are not even close to that?

[Choo Zhen Hao]

But the other 4 distribution are having a perfect parameter that suit the histogram. This is where i don't understand