MySQL Error Occurred

Error Message:
1055: Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'kidsdiar_kids.C.cat_id' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

SELECT DISTINCT(I.productId), C.cat_id, I.productCode, I.description, I.image, I.price,, I.popularity, I.sale_price, I.stock_level, I.useStockLevel FROM cubecart_cats_idx AS C INNER JOIN cubecart_inventory AS I ON C.productId = I.productId WHERE I.disabled = '0' AND C.cat_id > 0 and I.showFeatured=1 GROUP BY I.productId ORDER BY date_added DESC, name ASC