Office preview not working

i am using

  • LibreOffice 5.1.4.2 10m0(Build:2)
  • seafile server pro 6.0.1 beta
  • seafile behind apache with proxy/redirects, installed at non-root, eg. https://example.com/cloud

just tried it again. no logs when accessing a pdf or doc file.

i just stoped and started all again.
in seafenvents.log:

2016-10-13 12:36:56,702] [DEBUG] office enabled: True
[2016-10-13 12:36:56,702] [DEBUG] office convert workers: 1
[2016-10-13 12:36:56,702] [DEBUG] office outputdir: /tmp/
[2016-10-13 12:36:56,702] [DEBUG] office convert max pages: 50
[2016-10-13 12:36:56,702] [DEBUG] office convert max size: 2 MB
[2016-10-13 12:36:58,210] [DEBUG] Running command: "/usr/bin/python3" "/data/seafile/seafile-pro-server-6.0.1/pro/python/seafevents/office_converter/unoconv.py" "-vvv" "--pipe" "seafilepipe" "-l", cwd = /data/seafile/seafile-pro-server-6.0.1/pro/python/seafevents/office_converter
[2016-10-13 12:36:58,215] [INFO] office converter started

temp-file is created in /tmp, file is OK (moved in the docroot of apache)

in seafevents.log i get

[2016-10-13 12:40:15,100] [DEBUG] start to fetch task <type: doc, id: b88ab9...>
[2016-10-13 12:40:15,193] [DEBUG] start to convert task <type: doc, id:b88ab9...>

i now have two soffice processes

seafile  29776 29765  0 12:36 ?        00:00:00 /usr/lib/libreoffice/program/soffice.bin --invisible --nocrashreport --nodefault --nologo --nofirststartwizard --norestore --accept=pipe,name=seafilepipe;urp;StarOffice.ComponentContext
seafile  29856     1  0 12:40 ?        00:00:00 /usr/lib/libreoffice/program/soffice.bin --headless --invisible --nocrashreport --nodefault --nofirststartwizard --nologo --norestore --accept=pipe,name=seafilepipe;urp;StarOffice.ComponentContext