I installed calibre server onto a Oracle Cloud VPS (VM.Standard.E2.1.Micro shape AMD) with Ubuntu 22.04.1 LTS.
I followed
this guide for setup process.
I enable https traffic by Apache2 server with Let's Encrypt SSL certificate.
The calibre-server in /opt/calibre/bin folder has this data:
calibre-server: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=57d3ea3a6b36cb60362adfa135be0902776b3659, for GNU/Linux 3.2.0, stripped
-rwxr-xr-x 1 root root 14472 Dec 16 02:38 calibre-server
I'm using user authentication to access to calibre web domain.
Thanks