PDF documents can not be found on the server

I don't know, what's wrong here? I'm always getting the error message:

The requested document was not found on this server.

<script src="https://documentcloud.adobe.com/view-sdk/main.js"></script>
    <script type="text/javascript">
	document.addEventListener("adobe_dc_view_sdk.ready", function(){
           var name = '<?php echo $_GET["p3"]; ?>';
           var directory = 'https://domain.xy/resources/';
	   var adobeDCView = new AdobeDC.View({clientId: "key", divId: "adobe-dc-view"});
		       adobeDCView.previewFile({
			          content:{location: {url: directory.concat(name)}},
			          metaData:{fileName: name}
		       }, {embedMode: "SIZED_CONTAINER"});
	      });
    </script>

 The pdf-files are stored in the directory "resources" under the domain "domain.xy".