wp-admin timing out

I installed the Real Estate Web Builder plugin by Placester and I am unable to customize my site through the customize button (aka wp-admin). When I click on it, it takes me to the page and a menu of buttons shows up on the left side of the screen. In the center, it just shows a circular progress bar like its loading something. I have sat at this page for a couple of hours and nothing happens. When I deactivate the plugin, I can customize my theme like any other theme. This is the only plugin I have installed. Thanks for any info