MacOS is not copy-protected in the usual sense:
Apple software downloaded from the Mac App Store, including MacOS, is not copy protected. However, it IS tagged with the Apple-ID of the purchaser when "purchased" (or equivalent. Think of MacOS as purchased on sale for $0.)
You cannot update, upgrade, or install new software based on already-installed software UNLESS you supply the Apple-ID of the original software.
If your old MacOS is damaged, or you completely erased your Mac, the Apple-ID may not available, and you get the “cannot contact the server…” message that should go on to say, “…with the Apple-ID provided (or no Apple-ID)”.
Your Bare Mac computer IS eligible for the shipped-in-the-box version of macOS. When you invoke Recovery with Shift-Option-Command-R, you are requesting the "shipped-in-the-box" version, which is tagged ONLY with the serial number of your Mac, and does not require any Apple-ID to be already working on your Mac.
How to reinstall macOS - Apple Support