Error: Data structure returned is not convertible in the requested format: Multidimensional column values not supported. Found unexpected array value for column 'metrics' in row '0': 'array ( 'nb_visits' => 'Visits', 'nb_actions' => 'Actions', 'nb_pageviews' => 'Pageviews', 'revenue' => 'Revenue', 'nb_conversions' => 'Conversions', 'orders' => 'Ecommerce Orders', 'ecommerce_revenue' => 'Product Revenue', )'. Try to call this method with the parameters '&format=original&serialize=1'; you will get the original php data structure serialized.