Cannot communicate with WP

Hey there. In principle, it is a pretty cool tool to test snippets etc.

But I cannot communicate with WP. I simply try to get some values from the database to check if it is possible to interact with the system but it fails.

If I try to get something from the database, eg with

_dump( get_option( ‘siteurl’ ) );

then it throws some errors related to the RestController:

#0 /var/www/vhosts/folder.de/domain.com/public_html/wp-content/plugins/wp-console/includes/Core/Console/RestController.php(137) : eval()'d code(7): WPConsole\Core\Console\Psy\Shell->handleError(8, 'Undefined prope...', '/var/www/vhosts...', 7, Array)
#1 /var/www/vhosts/folder.de/domain.com/public_html/wp-content/plugins/wp-console/includes/Core/Console/RestController.php(137): eval()
#2 /var/www/vhosts/folder.de/domain.com/public_html/wp-includes/rest-api/class-wp-rest-server.php(1143): WPConsole\Core\Console\RestController->create_item(Object(WP_REST_Request))
#3 /var/www/vhosts/folder.de/domain.com/public_html/wp-includes/rest-api/class-wp-rest-server.php(990): WP_REST_Server->respond_to_request(Object(WP_REST_Request), '/wp-console/v1/...', Array, NULL)
#4 /var/www/vhosts/folder.de/domain.com/public_html/wp-includes/rest-api/class-wp-rest-server.php(414): WP_REST_Server->dispatch(Object(WP_REST_Request))
#5 /var/www/vhosts/folder.de/domain.com/public_html/wp-includes/rest-api.php(394): WP_REST_Server->serve_request('/wp-console/v1/...')
#6 /var/www/vhosts/folder.de/domain.com/public_html/wp-includes/class-wp-hook.php(307): rest_api_loaded(Object(WP))
#7 /var/www/vhosts/folder.de/domain.com/public_html/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters('', Array)
#8 /var/www/vhosts/folder.de/domain.com/public_html/wp-includes/plugin.php(524): WP_Hook->do_action(Array)
#9 /var/www/vhosts/folder.de/domain.com/public_html/wp-includes/class-wp.php(398): do_action_ref_array('parse_request', Array)
#10 /var/www/vhosts/folder.de/domain.com/public_html/wp-includes/class-wp.php(770): WP->parse_request('')
#11 /var/www/vhosts/folder.de/domain.com/public_html/wp-includes/functions.php(1330): WP->main('')
#12 /var/www/vhosts/folder.de/domain.com/public_html/wp-blog-header.php(16): wp()
#13 /var/www/vhosts/folder.de/domain.com/public_html/index.php(17): require('/var/www/vhosts...')
#14 {main}

Any idea how to fix it?