Collabora package for Debian 9 not working - Internal server error

Hi, I just migrated my Nextcloud from an Ubuntu Server VM to it’s debian 9 host. Previously I used the docker container, now I tried to install the native package. It seems to have installed properly.
I have set up a reverse proxy with the standard config foung on collaboras website (I only changed the domain).
When I try to open a document from Nextcloud, I get the Internal Server Error screen.

The loolwsd service status: sudo service loolwsd status
● loolwsd.service - LibreOffice Online WebSocket Daemon
Loaded: loaded (/lib/systemd/system/loolwsd.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Sun 2017-10-22 16:18:21 CEST; 4s ago
Process: 1548 ExecStart=/usr/bin/loolwsd --version --o:sys_template_path=/opt/lool/systemplate --o:lo_template_path=/opt/collaboraoffice5.3 --o:child_root_
Main PID: 1548 (code=exited, status=70)

Okt 22 16:18:21 debianserver systemd[1]: loolwsd.service: Main process exited, code=exited, status=70/n/a
Okt 22 16:18:21 debianserver systemd[1]: loolwsd.service: Unit entered failed state.
Okt 22 16:18:21 debianserver systemd[1]: loolwsd.service: Failed with result 'exit-code'.
Okt 22 16:18:21 debianserver systemd[1]: loolwsd.service: Service hold-off time over, scheduling restart.
Okt 22 16:18:21 debianserver systemd[1]: Stopped LibreOffice Online WebSocket Daemon.
Okt 22 16:18:21 debianserver systemd[1]: loolwsd.service: Start request repeated too quickly.
Okt 22 16:18:21 debianserver systemd[1]: Failed to start LibreOffice Online WebSocket Daemon.
Okt 22 16:18:21 debianserver systemd[1]: loolwsd.service: Unit entered failed state.
Okt 22 16:18:21 debianserver systemd[1]: loolwsd.service: Failed with result 'exit-code'.

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I tried to start the process multiple times, resulting in similar errors. Any ideas what might we wrong? I can provide other logfiles if you need them.

Regards, Getriebesand

Any ideas?

I had trouble too. check https://help.nextcloud.com/t/native-debian-9-collabora-package-does-not-install-correctly/21191/13

if you used docker on the same machine before, check your firewallD (if it is installed) It may block docker stuff.