上传待处理的文件

Question

I have a web application running on server 2012 with IIS and php version 5.5.11.

I have a simple form for uploading files to the server

<div class="pdfupload">
<h1>upload files</h1>                   
        <form action="/<?php echo $user?>/upload" method="POST" enctype="multipart/form-data">
        <input type="file" name="files[]" multiple />
        <input type="hidden" name="test_id" />
        <input type="hidden" name="points" />
        <input class="uploadpdfsubmit" type="submit" value="upload files" />
    </form>
</div>

the form worked fine and I was able to upload my files, until a few days ago. now only some of the files get uploaded (notepad or empty doc files will upload but pdf or doc with content wont upload) its not a size related isuue cause i was able to upload a very big notepad file.

the problem only accurs while im connected to my home network - i tried 3 other networks and there was no problem.

the files that wont upload get stuck on pending - and by going to the network tab in chrome i see that the request isnt created properly. under headers i see a warning sign with Provisional headers are shown.

i have no idea what i causing this strang behavior