Export Service generates empty PDF on windows server


i have a local application running with the scheduler and export server and everything is working fine. Data will be processed by the local export server and the PDF is generated.

However, after i installed everything on our Windows Server, the export server is replying with an empty pdf.

Data, Export Server and application code is the same as on my local machine and i dont get why there is nothing in the PDF. Not just an empty Calendar, but the whole PDF is 0kb size as you can see in the screenshot below.

The scheduler data is send to “http://localhost:3200/scheduler” since the export server runs locally for the application on the windows server.

Any ideas what the problem could be?