Export file download, console output garbled code

Question

header("Pragma: public"); header("Expires: 0"); header("Cache-Control:must-revalidate, post-check=0, pre-check=0"); header("Content -Type:application/force-download"); header("Content-Type:application/vnd.ms-execl"); header("Content-Type:application/octet-stream"); ​​header("Content-Type: application/download");; header('Content-Disposition:attachment;filename='.$fileName.''); header("Content-Transfer-Encoding:binary");//output $writer = IOFactory::createWriter ($spreadsheet,'Xlsx'); $writer->save('php://output');

But if

$writer->save('filename' );

can be saved directly in the root directory, but cannot be downloaded

Answer 1

Code and error message, screenshots will be sent