Custom Sidebars not working properly

I've installed the custom sidebar plugin but whenever I go to do anything with it, I get a never ending time circle. For example, if I click on "sidebar location", I get this... https://www.dropbox.com/s/3uzknumcec1037l/Screen%20Shot%202016-10-06%20at%204.18.33%20pm.png?dl=0 displaying but then nothing. Eventually, I see an error that says, "Couldn't load data from WordPress" like this... https://www.dropbox.com/s/om1z2wlsoi8v9ih/Screen%20Shot%202016-10-06%20at%204.20.39%20pm.png?dl=0