[Koha] Empty PDF file when printing labels

[Franz Dietrich]

Hey all,
I can't figure out the problem on my own right now.
 
Problem:
Label creator ->manage->label batches->select one->export(full or single)->select the options->select PDF
A PDF-Editor opens but no pdf is shown. If I download the pdf it says corrupt (the file is 0 Bytes)
 
I can't find any logs on the server mentioning an issue. The only thing I can find is - which is a 200 Responsecode...:
 
http://redacted.cloud:80 http://192.168.20.174 - - [07/Jul/2022:07:15:01 +0000] "GET /cgi-bin/koha/labels/http://label-create-pdf.pl?batch_id=2&template_id=25&layout_id=24&start_label=1 HTTP/1.1" 200 308 "http://redacted.cloud/cgi-bin/koha/labels/label-print.pl" "Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0"
 
what could be next steps to find the issue?