mPDF - 临时文件目录...不可写

Question

I 'm using mPDF 7.1 (via composer) and i have a problem with "Temporary files directory".

Can anyone tell me why this is always saying that the directory is not writable, when it absolutely is?

I am on my server and i have tested it with all folders. Same error message.

This is a sample of my code:

<?php
require_once($_SERVER["DOCUMENT_ROOT"] . "/library/tools/mpdf7/vendor/autoload.php"); // include MPDF library

function generateInvoice()
{
    try 
    {           
        $mpdf = new \Mpdf\Mpdf([
           "tempDir" => __DIR__ . "/custom/temp/dir/path"
        ]);

        $mpdf->WriteHTML("<h1>Hello World!</h1>");
        $mpdf->Output();

        return true;
    } 
    catch(\Mpdf\MpdfException $e) 
    {
        echo $e->getMessage();

        return false;
    }
}