the file type you are attempting to upload is not allowed. codeigniter xls

add to your config/mimes.php types 'application/octet-stream'

'xls' => array('application/vnd.openxmlformats-officedocument.spreadsheetml.sheet', 'application/zip', 'application/x-zip', 'application/vnd.ms-excel', 'application/msexcel','application/excel','application/vnd.ms-office'),