Onlyoffice as editor in PHP

Docs API
1

I tried to integrate Onlyoffice into an existing app. Onlyoffice Document Server is installed on a different server than the original app. Using the php example code, I cannot get the document server to load my documents, what am I doing wrong?
Disclaimer: I needed to modify the code for PHP < 7 compatibility.

The onlyoffice instance is running well, I have enabled the example as recommended.
Maybe I am missing something, but it seems as if the onlyoffice instance is not able to fetch the documents.

$GLOBALS['DOC_SERV_SITE_URL'] = "https://app.server.com/onlyoffice/";

$GLOBALS['DOC_SERV_CONVERTER_URL'] = "http://onlyofficeserver.com:8085/ConvertService.ashx";
$GLOBALS['DOC_SERV_API_URL'] = "http://onlyofficeserver.com:8085/web-apps/apps/api/documents/api.js";
$GLOBALS['DOC_SERV_PRELOADER_URL'] = "http://onlyofficeserver.com:8085/web-apps/apps/api/documents/cache-scripts.html";
$GLOBALS['DOC_SERV_COMMAND_URL'] = "http://onlyofficeserver.com:8085/coauthoring/CommandService.ashx";

$GLOBALS['DOC_SERV_JWT_SECRET'] = "";
$GLOBALS['DOC_SERV_JWT_HEADER'] = "Authorization";

$GLOBALS['EXAMPLE_URL'] = "https://app.server.com/onlyoffice";
2

Hello,
Please follow the guide ONLYOFFICE Api Documentation - Example
It clearly says to change only
$GLOBALS['DOC_SERV_SITE_URL'] = "https://documentserver/";
Other lines should remain unchanged. So the section must look like this:

$GLOBALS['DOC_SERV_SITE_URL'] = "https://address-of-your-document-server/";

$GLOBALS['DOC_SERV_CONVERTER_URL'] = "ConvertService.ashx";
$GLOBALS['DOC_SERV_API_URL'] = "web-apps/apps/api/documents/api.js";
$GLOBALS['DOC_SERV_PRELOADER_URL'] = "web-apps/apps/api/documents/cache-scripts.html";
$GLOBALS['DOC_SERV_COMMAND_URL'] = "coauthoring/CommandService.ashx";

$GLOBALS['DOC_SERV_JWT_SECRET'] = "";
$GLOBALS['DOC_SERV_JWT_HEADER'] = "Authorization";

$GLOBALS['EXAMPLE_URL'] = "";