Rendering stuck on Upfront created theme

Hello. I created a custom theme based off of the uf-scribe theme using the Upfront builder installed on (support access granted). I've exported the theme and installed it with Upfront builder + core on another site (support access granted). I'd like to continue editing and customizing the theme on since that is the site that will be using it. However, whenever I try to open Upfront builder to edit the theme it stops rendering at 51% everytime. Upfront builder works perfectly fine with your themes (for example I installed Fixer) and there's no problem. This is a fresh WP install and I was having it stop at 51% on another domain with upfront builder. So I think it has something to do with the theme I created but I don't know where to start as all exports from are doing this, even though it works fine on

I appreciate any help. Thank you!