Error 500 when trying to insert file into a zip - php

Question

I wrote a function to generate a zip file.
See the code below.
This function works fine in wamp with php 7.2.10.
It also worked fine on the web server with php 7.2.18 but a problem occured after upgrading php to version 7.3.5.
The zip file is created, the directory images inside the zip is created, but it crashes with an error 500 when trying to add file to the zip.
Here are the error logs generated
[Fri Oct 09 08:59:43.382099 2020] [fcgid:warn] [pid 22236] (104)Connection reset by peer: [client ] mod_fcgid: error reading data from FastCGI server, referer:
[Fri Oct 09 08:59:43.382149 2020] [core:error] [pid 22236] [client ] End of script output before headers: index.php, referer:
Thanks in advance for your help
function createZIP($source,$destination)
{
$files=scandir($source.'/images',1);
$files= array_diff($files, array('..', '.'));
$zip = new ZipArchive;
$res = $zip->open($destination, ZipArchive::CREATE);
if ($res === TRUE)
{
if($zip->addEmptyDir('images'))
{
foreach ($files as $value)
{
$zip->addFile($source.'/images/'.$value, 'images/'.$value);
}
$zip->addFile($source.'/signature_client_lourd.html', 'signature_client_lourd.html');
$zip->addFile($source.'/signature_client_leger.txt', 'signature_client_leger.txt');
$zip->close();
return true;
}
else
{
return false;
}
}
else
{
return false;
}
}