I'm not sure what causes this error, but this is from the "Your Site is Experiencing a Technical Issue" email:
An error of type E_ERROR was caused in line 22 of the file /www/wp-content/plugins/meta-box-aio/vendor/meta-box/meta-box-beaver-themer-integrator/meta-box-beaver-themer-integrator.php. Error message: Uncaught Error: Class 'MBBTI\Posts' not found in /www/wp-content/plugins/meta-box-aio/vendor/meta-box/meta-box-beaver-themer-integrator/meta-box-beaver-themer-integrator.php:22
Stack trace:
#0 /www/wp-content/plugins/meta-box-aio/src/Loader.php(23): require_once()
#1 /wordpress/wp-includes/class-wp-hook.php(308): MBAIO\Loader->load_extensions(Array)
#2 /wordpress/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters(NULL, Array)
#3 /wordpress/wp-includes/plugin.php(517): WP_Hook->do_action(Array)
#4 /wordpress/wp-settings.php(620): do_action('init')
#5 /www/wp-config.php(110): require_once('/wordpress/wp-s...')
#6 /wordpress/wp-config.php(5): require('/www/wp-config....')
#7 /wordpress/wp-load.php(50): require_once('/wordpress/wp-c...')
#8 /wordpress/wp-login.php(12): require('/wordpress/wp-l...')
#9 {main}
.
