whenever I try

whenever I try to use upfront builder, I only get a blank white screen or the site's navigation/admin bar with no CSS styling. I have tried to make a new theme from scratch theme as well as modify one of your existing themes and neither worked.

At one point, I got locked out of my site with a "you are not authorize to access this page" error and had to start from scratch. I have tried the plugin on a plain fresh install and and no other plugins and cannot get it to work. I'm using siteground hosting and using cloudflare but turning off cloudflare didn't make a difference. Please help me resolve this. Thanks.