Siteground Optimizer causing white page

I have been getting an error where my page shows as only a white page when not logged in. I disabled all plugins and re enabled them one by one and determined it is caused by the Siteground Optimizer plug in. I am using the avada theme. However, whenever I update my site using Avada, the CSS breaks and I have to re enable Siteground Optimizer (to get the white screen) and then disable it again to get the page to load correctly.

I’ve searched around online the past week and haven’t found an answer so far.

Thank you for your help.

The page I need help with: [log in to see the link]