Theme Customization Menu

I am using the Bretheon theme created by MuffinGroup running on WordPress 3.9 and hosted by GoDaddy.

Without any notice, I am no longer able to run any sort of customization from the “customize” option within my dashboard menu. It allows me to click and navigate to the page, but leaves with with a blank screen with no content. My connection is good and I can edit and customize withing my other sites I help run, just not on this one.

Here is an image of what the screen looks like :

https://awesomescreenshot.com/00a2s2y368

Any support or suggestions would be appreciated. Thank you.