ss -ln | grep 8080
tcp LISTEN 0 128 0.0.0.0:8080 0.0.0.0:*
The server address is 192.168.1.69. If a browser on the server points to:
http://192.168.1.69:8080 it shows the initial page of Calibre with this warning:
"WARNING: This browser does not support Application Cache so offline access to Calibre will not work. Some browsers enable Application Cache only on HTTPS connections, so you may need to configure HTTPS for your Calibre server."
and after I can click on the library icon to see the content.
With
http://192.168.1.69:8080/mobile I go directly to the content of library, as it should be, I think.