Same here.
Error Details
=============
An error of type E_ERROR was caused in line 35 of the file /var/www/domain/htdocs/wp-content/plugins/meta-box-aio/vendor/meta-box/meta-box-builder/bootstrap.php. Error message: Uncaught Error: Class 'MBB\Extensions\RestApi' not found in /var/www/domain/htdocs/wp-content/plugins/meta-box-aio/vendor/meta-box/meta-box-builder/bootstrap.php:35
Stack trace:
#0 /var/www/domain/htdocs/wp-content/plugins/meta-box-aio/vendor/meta-box/meta-box-builder/meta-box-builder.php(41): require()
#1 /var/www/domain/htdocs/wp-includes/class-wp-hook.php(307): mb_builder_load()
#2 /var/www/domain/htdocs/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters()
#3 /var/www/domain/htdocs/wp-includes/plugin.php(476): WP_Hook->do_action()
#4 /var/www/domain/htdocs/wp-settings.php(598): do_action()
#5 /var/www/domain/wp-config.php(133): require_once('/var/www/stagin...')
#6 /var/www/domain/htdocs/wp-load.php(55): require_once('/var/www/stagin...')
#7 /var/www/domain/htdocs/wp-admin/admin-ajax.php(22): require_once('/var/w
