Hi @tomen,
from the error code I can see that you have fatal errors in
PHP Fatal error: Uncaught Error: Call to undefined function is_checkout() in /wp-content/themes/flatsome-child/functions.php:219 Stack trace:
and
PHP Fatal error: require(): Failed opening required ‘ABSPATHwp-includes/version.php’ (include_path=’.:/opt/php/7.4/lib/php’) in /smart-things-sta/wp-settings.php on line 33 [04-Aug-2023 14:21:00 Europe/Berlin] PHP Warning: Use of undefined constant ABSPATH – assumed ‘ABSPATH’ (this will throw an Error in a future version of PHP) in /smart-things-sta/wp-settings.php on line 33
I recommend that you check the recent changes that you did on your theme /flatsome-child and on /smart-things-sta/
These errors are unrelated to wp staging and have not been caused by the wp staging plugin.
If you created a backup with wp staging, you can use that one to restore your website.
Please let me know how it goes.