Cannot open or edit documents on the example server

Hi everyone! I just installed OnlyOffice document server via docker to use with my Nextcloud setup. Installation went well, I can access the welcome page of OnlyOffice and started the test example server to see what it looks like. However, when I open a document, I am first faced with a long document loading and then with the error message “The file cannot be accessed right now”.
Also, when I try to integrate OnlyOffice to my Nextcloud, I does not work. But I believe solving this configuration issue I have with the test example will also help me with Nextcloud.
I looked up a bunch of youtube tutorials and posts on various forums but it didn’t help, unfortunately.

Any ideas on what may be wrong ?

Document Server version: latest (I installed it a few days ago)
Type of installation of the Document Server : Docker
OS: Ubuntu 22.04
Browser version: Firefow 124.0.1

Please provide the following additional info:

  1. The version of installed Document Server
  2. Document Server logs as a file (/var/log/onlyoffice/documentserver inside the container)