Php to achieve file download, web download is no problem, but the content of the file downloaded on the mobile phone is actually the content of the current html set of php files, what is the reason?

php implements file download, but the file downloaded on the web side is fine, but the content of the file downloaded on the mobile phone is actually the content of the current html set of php files. What is the reason for this?

    $path =  IA_ROOT."/".$datum["file_path"];

            $file_name  = substr($datum["file_path"],strrpos($datum["file_path"],"/")+1);
//            $file = fopen($path,"r"); // 
//            $file_size=filesize($path);
            header("Content-Type: application/octet-stream");
            header("Content-Disposition: attachment; filename=".$file_name);
            header("Accept-ranges:bytes");

            header("Content-Transfer-Encoding: binary");
            readfile($path);
Aug.09,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b318fd-2bd9e.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b318fd-2bd9e.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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