I created the server.key and server.csr files using openssl req -nodes -newkey rsa:2048 -keyout server.key -out server.csr. I created a SSL certificate with sta
I know this is an old question, but I encountered the same thing today. I would get the same result back from express (ERR_EMPTY_RESPONSE).
The fix? Be sure to specify https, and not http, in your test browser (e.g., https://localhost:8443).
If you previously used middleware to forward all http requests to https you wouldn't have seen this problem before. Also, expect your browser to complain about the certificate, but proceed through anyway (in chrome this takes several clicks).