Collabora Online isn't working, internal server error by open ducuments

Hello everybody,

at first sorry for my english.

I tried to install and use Collabora Online on a Ubuntu Server 16.04 LTS with Apache-Webserver 2.4.18 and all recommended mudules.

My Nextcloud is version 12, Collabora online was installed by using official tutorial on (“Getting started in 3 steps”). The docker container is started, the collabora Online App is activated. Nextcloud is working fine.

The problem: when I try to open an office-file in Nextcloud for editing I get an internal server error (because the german installation the error-text is german, too):

Interner Serverfehler
Der Server hat einen internen Fehler und konnte Ihre Anfrage nicht vervollständigen.
Bitte wenden Sie sich an den Serveradministrator, wenn dieser Fehler mehrfach auftritt, geben Sie bitte die, unten stehenden, technischen Details in Ihrem Bericht mit an.
Weitere Details können im Server-Protokoll gefunden werden.
Technische Details
Entfernte Adresse:
Anfragekennung: ATbYOnnpBPl1EpMJOygI

In the nextcloud-log I can found the request and there is the following additional error:
“cURL error 56: Received HTTP code 403 from proxy after CONNECT”.

I don’t know what to do. I guess that there is a problem with the configured reverse proxy (extra virtual host like in the tutorial). It seems like the proxy has no connection with docker.

This is my virtual host config:

<VirtualHost *:443>

SSL configuration, you may want to take the easy route instead and use Lets Encrypt!

SSLEngine on
SSLCertificateFile /etc/ssl/certs/cert-xxxxxxxxxxxxxxxxxxxxxxxxx.pem
SSLCertificateChainFile /etc/ssl/private/chain.txt
SSLCertificateKeyFile /etc/ssl/private/myoffice.server.de_key.pem
SSLProtocol all -SSLv2 -SSLv3
SSLHonorCipherOrder on

Encoded slashes need to be allowed

AllowEncodedSlashes NoDecode

Container uses a unique non-signed certificate

SSLProxyEngine On
SSLProxyVerify None
SSLProxyCheckPeerCN Off
SSLProxyCheckPeerName Off

keep the host

ProxyPreserveHost On

static html, js, images, etc. served from loolwsd

loleaflet is the client part of LibreOffice Online

ProxyPass /loleaflet retry=0
ProxyPassReverse /loleaflet

WOPI discovery URL

ProxyPass /hosting/discovery retry=0
ProxyPassReverse /hosting/discovery

Main websocket

ProxyPassMatch “/lool/(.*)/ws$” wss://$1/ws nocanon

Admin Console websocket

ProxyPass /lool/adminws wss://

Download as, Fullscreen presentation and Image upload operations

ProxyPass /lool
ProxyPassReverse /lool


If more info is needed I will provide it soon.

Thanks in advance for all help.


What kind of SSL certificate do you have for Did you anonymize the SSL parts in your vhost config or do you have those entries as seen in this post?

You need a separate cert (letsencrypt) for . Then in vhost config you’ll have something like:

# Letsencrypt certificate
SSLCertificateFile      /etc/letsencrypt/live/
SSLCertificateKeyFile /etc/letsencrypt/live/

instead of all those SSL entries I’ve seen in your config.

Or maybe I misunderstood something?

I have an official server certificate. Yes, the SSL-parts in the vhost cobfig are anonymized (server-name and certificate-name).


No further hints for me? I’m in a dead end…