Hi @Nikolas
I appreciate your help.
I am a new user and I am trying to understand the mechanics of the document service.
When I installed workspace, my main goal was to use project and CRM. I added documents to my projects and it worked (on the 1st day) without me setting up the document service. I did add a webdav location for backups but never added a location for the doc-server, never looked like I needed to setup anything to use documents.
I ran the commands you sent me and this is what I got:
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telmo@onlyoffice:~$ apt list --installed | grep onlyoffice
WARNING: apt does not have a stable CLI interface. Use with caution in scripts.
onlyoffice-communityserver/squeeze,now 12.1.0.1760 all [installed]
onlyoffice-controlpanel/squeeze,now 3.1.1.467 all [installed]
onlyoffice-documentserver/squeeze,now 7.3.3-49~stretch amd64 [installed]
onlyoffice-xmppserver/squeeze,now 12.0.0.120 all [installed]
telmo@onlyoffice:~$ netstat -tulpn
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:9812 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:8084 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9813 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9814 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9815 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9816 0.0.0.0:* LISTEN -
tcp 0 0 127.0.0.1:5432 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9817 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9882 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9883 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9884 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9885 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9886 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:5280 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:5025 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:5026 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:5222 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:5031 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:5032 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:25672 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9865 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9866 0.0.0.0:* LISTEN -
tcp 0 0 127.0.0.1:6379 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9807 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9871 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9808 0.0.0.0:* LISTEN -
tcp 0 0 127.0.0.1:5232 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:8083 0.0.0.0:* LISTEN -
tcp 0 0 0.0.0.0:9811 0.0.0.0:* LISTEN -
tcp6 0 0 127.0.0.1:9300 :::* LISTEN -
tcp6 0 0 ::1:9300 :::* LISTEN -
tcp6 0 0 :::22 :::* LISTEN -
tcp6 0 0 ::1:5432 :::* LISTEN -
tcp6 0 0 :::9889 :::* LISTEN -
tcp6 0 0 :::33060 :::* LISTEN -
tcp6 0 0 :::5672 :::* LISTEN -
tcp6 0 0 :::9800 :::* LISTEN -
tcp6 0 0 :::9834 :::* LISTEN -
tcp6 0 0 :::3306 :::* LISTEN -
tcp6 0 0 :::9899 :::* LISTEN -
tcp6 0 0 :::9999 :::* LISTEN -
tcp6 0 0 127.0.0.1:9200 :::* LISTEN -
tcp6 0 0 ::1:9200 :::* LISTEN -
tcp6 0 0 ::1:5232 :::* LISTEN -
tcp6 0 0 :::4369 :::* LISTEN -
tcp6 0 0 :::8082 :::* LISTEN -
tcp6 0 0 :::8083 :::* LISTEN -
udp 0 0 0.0.0.0:68 0.0.0.0:* -
telmo@onlyoffice:~$
==//===
When testing and trying to figure out where my problem is, I noticed that now my control panel screen also doesn’t load 
And I tried to open the document-server page on my browser and it opened.