Download the docket as PDF file: empty PDF

We have problems with download dockets as PDF. A file is downloaded, but it is empty.

Error in goobi.log:

2022-06-28 09:57:49 DEBUG Process:1381 - generate docket for process 46
2022-06-28 09:57:49 ERROR Process:1408 - IOException while exporting run note FOPException occured
        at io.goobi.workflow.xslt.XsltToPdf.startExport( ~[classes/:f7c7afed22]


Caused by: org.apache.fop.apps.FOPException: .fop (Permission denied)

Do you know where the .fop file is supposed to be saved?