Error Orders

I am getting this error under orders (admin section):

COLLATION 'utf8_general_ci' is not valid for CHARACTER SET 'utf8mb4' SQL=SELECT a.*,b.*,c.*,IFNULL(c.name COLLATE utf8_general_ci,CONCAT_WS(' ',d.address_firstname,d.address_middle_name,d.address_lastname)) AS hikashop_name FROM #__hikashop_order AS b LEFT JOIN #__hikashop_address AS d ON b.order_billing_address_id=d.address_id LEFT JOIN #__hikashop_user AS a ON b.order_user_id=a.user_id LEFT JOIN #__users AS c ON a.user_cms_id=c.id WHERE (b.order_type='sale') ORDER BY b.order_id desc LIMIT 0, 20