My website will run at Wifi hotspots, meaning that the server will have a LAN IP address from a local router. WAN access may or may not be available reliably at these locations. I plan to use the same domain name for each server (i.e. when a user connects to the hotspot, they will be able to access my website using the URL https://mywebsite.mydomain.com). The hotspot router will be configured to resolve this DNS name to my server’s LAN IP address.
How can I use LetsEncrypt certificates on my local servers to secure my website?