Website Error

Whenever I have the Stackable – Gutenberg Blocks activated I cannot customise my current Theme (Education Minimal Pro). I get the error:-

“The site is experiencing technical difficulties. Please check your site admin email inbox for instructions”.

I can deactivate the plugin and customise with no problem but as soon as I re-activate the same problem occurs. Please advise how we go about fixing the incompatibility between the theme and the plugin.

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