Office preview and Onlyoffice

Tried to install yesterday Onlyoffice (on Ubuntu 19). Installed via Docker. And using Apache. After some hickups (mainly getting it working with Apache) was able to create a docx file out of seafile. However when trying to edit only empty page was shown. And the file got a “locked by Onlyoffice” sign.

So I assume that I need to first uninstall Office preview (using Libreoffice) before I try another time to install Onlyoffice? Has somebody made this experience and can advise?

This usually means that the onlyoffice server cant be reached.

Im not into apache so i cant help you with the reverse proxy setup (if you use any), but i would start looking in the error.log from apache.

Try to reach the onlyoffice server directly via apache. Is this avaliable?
usually you can reach it via domain.tld/onlyofficeds/welcome/