PHP COM(Html to docx) $word->ActiveDocument->SaveAs() having Uncaught com_exception: Parameter 0: Type mismatch

Question

Here we are using php COM(word.application) for converting the html to docx. But COM("word.application")->ActiveDocument->SaveAs($htmlfilepath, 16) function is giving the below mentioned error. Uncaught com_exception: Parameter 0: Type mismatch.

// WdSaveFormat: http://msdn.microsoft.com/en-us/library/office/bb238158%28v=office.12%29.aspx
static $wdSaveFormats = array(
    'docx' => 16,
    'html' => 10,
    'rtf'  => 6,
    'txt'  => 2,
    'doc'  => 0,
    'pdf'  => 17,
);
$newSaveFormat = 16;
if (preg_match('@\.(.{3,4})$@', $new, $arr)) {
    if (isset($wdSaveFormats[$arr[1]])) {
        $newSaveFormat = $wdSaveFormats[$arr[1]];
    }
}

$rethrow = NULL;
try {
    // Document.Enable long file name https://msdn.microsoft.com/en-us/vba/word-vba/articles/weboptions-uselongfilenames-property-word
    $word->ActiveDocument->WebOptions->UseLongFileNames = true;

    // Document.SaveAs: http://msdn.microsoft.com/en-us/library/office/bb221597%28v=office.12%29.aspx
    // $new = 'Z:\data\reportPdf/1636634123sampl_test_2019programreport.docx';
    **$word->ActiveDocument->SaveAs($new, $newSaveFormat);**
} catch (Exception $rethrow) {
    // We still want to close the document.
}

Thanks in advance!