Collabora Document Server unavailable

Installation & Configuration
1

Hello,

I am currently setting up a document server for my Nextcloud.
This has worked quite well so far. The server is accessible via the internal IP and gives the desired output.

However, when I try to access the server via my domain, I only get the default Apache2 page from my reverse proxy instead of the page that opens when I access it via the internal IP. This also prevents me from adding the server to Nextcloud.
To set up the server I followed this tutorial: Integrate Collabora Online with Nextcloud on Ubuntu without Docker

I got the Apache Reverse Proxy Config from this tutorial: HowTo: Ubuntu + Docker + Nextcloud + Talk + Collabora - 📑 How to - Nextcloud community

<VirtualHost *:80>
  ServerName office.domain.eu
  ErrorLog ${APACHE_LOG_DIR}/error.log
  CustomLog ${APACHE_LOG_DIR}/access.log combined
  AllowEncodedSlashes NoDecode
  SSLProxyEngine On
  SSLProxyVerify None
  SSLProxyCheckPeerCN Off
  SSLProxyCheckPeerName Off
  ProxyPreserveHost Off
  ProxyPass           /loleaflet https://192.168.178.134:9980/loleaflet retry=0
  ProxyPassReverse    /loleaflet https://192.168.178.134:9980/loleaflet
  ProxyPass           /hosting/discovery https://192.168.178.134:9980/hosting/discovery retry=0
  ProxyPassReverse    /hosting/discovery https://192.168.178.134:9980/hosting/discovery
  ProxyPassMatch "/lool/(.*)/ws$" wss://192.168.178.134:9980/lool/$1/ws nocanon
  ProxyPass   /lool/adminws wss://192.168.178.134:9980/lool/adminws
  ProxyPass           /lool https://192.168.178.134:9980/lool
  ProxyPassReverse    /lool https://192.168.178.134:9980/lool
  ProxyPass           /hosting/capabilities https://192.168.178.134:9980/hosting/capabilities retry=0
  ProxyPassReverse    /hosting/capabilities https://192.168.178.134:9980/hosting/capabilities
RewriteEngine on
RewriteCond %{SERVER_NAME} =office.domain.eu
RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]
</VirtualHost>

<VirtualHost *:443>
  ServerName office.domain.eu
  ErrorLog ${APACHE_LOG_DIR}/error.log
  CustomLog ${APACHE_LOG_DIR}/access.log combined
  SSLEngine on
  AllowEncodedSlashes NoDecode
  SSLProxyEngine On
  SSLProxyVerify None
  SSLProxyCheckPeerCN Off
  SSLProxyCheckPeerName Off
  ProxyPreserveHost On
  ProxyPass /loleaflet https://192.168.178.134:9980/loleaflet retry=0
  ProxyPassReverse /loleaflet https://192.168.178.134:9980/loleaflet
  ProxyPass /hosting/discovery https://192.168.178.134:9980/hosting/discovery retry=0
  ProxyPassReverse /hosting/discovery https://192.168.178.134:9980/hosting/discovery
  ProxyPassMatch "/lool/(.*)/ws$" wss://192.168.178.134:9980/lool/$1/ws nocanon
  ProxyPass /lool/adminws wss://192.168.178.134:9980/lool/adminws
  ProxyPass /lool https://192.168.178.134:9980/lool
  ProxyPassReverse /lool https://192.168.178.134:9980/lool
  ProxyPass /hosting/capabilities https://192.168.178.134:9980/hosting/capabilities retry=0
  ProxyPassReverse /hosting/capabilities https://192.168.178.134:9980/hosting/capabilities
  SSLCertificateFile      /etc/letsencrypt/live/office.domain.eu/fullchain.pem
  SSLCertificateKeyFile /etc/letsencrypt/live/office.domain.eu/privkey.pem
Include /etc/letsencrypt/options-ssl-apache.conf
</VirtualHost>

That’s the Output of my error.log:
I have to say that the hours in the logs are not correct. The minutes, however, are, between posting this post and the last log entry are over half an hour in which I went several times on domain. So Apache does not create regular logs.

[Wed Oct 12 06:06:59.806139 2022] [proxy:error] [pid 2906:tid 139860411946752] (20014)Internal error (specific information not available): [client ExternalIP:50355] AH01084: pass request body failed to 192.168.178.134:9980 (192.168.178.134)
[Wed Oct 12 06:06:59.806197 2022] [proxy:error] [pid 2906:tid 139860411946752] [client ExternalIP:50355] AH00898: Error during SSL Handshake with remote server returned by /hosting/discovery
[Wed Oct 12 06:06:59.806204 2022] [proxy_http:error] [pid 2906:tid 139860411946752] [client ExternalIP:50355] AH01097: pass request body failed to 192.168.178.134:9980 (192.168.178.134) from ExternalIP()

This is the entry in the access.log from my last access to the domain.

ExternalIP - - [12/Oct/2022:06:38:06 +0000] "GET / HTTP/2.0" 200 3381 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36"
ExternalIP - - [12/Oct/2022:06:38:06 +0000] "GET /icons/ubuntu-logo.png HTTP/2.0" 200 3536 "https://office.domain.eu/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36"
ExternalIP - - [12/Oct/2022:06:38:06 +0000] "GET /favicon.ico HTTP/2.0" 404 414 "https://office.domain.eu/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.0.0 Safari/537.36"

If there is any additional info missing, feel free to contact me anytime.