Kodi Community Forum

I recently discovered that Kodi has a built-in web interface. For no particular reason, I set it up with my own local HTTPS certificate. (: Of course, this means any other device that wants to use HTTPS with the web interface gets a certificate error.

So I tried accessing Kodi with plain HTTP, but that says "the connection was reset".

Can I support HTTPS for those who want it, but leave plain HTTP available for devices that don't have the certificate?

that's currently not possible with the built in webserver. Its either https or http.
You can however put a reverse proxy (apache, nginx, haproxy,...) in front of kodi that handles both.