Theme error – Website blank/white page

Hello,

I built my website on Neve using Elementor and Elementor header & footer builder.
It was working very well on my staging domain dev.living-labs.org

I transferred the website to my main domain living-labs.org. When propagation was over, only a blank/white page appeared. An error in the source code was error-theme.

I now changed to another theme to access backend but lost my UX. If I revert back to Neve, the same error appears.

Can someone help?

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