Are you sure your router isn’t intercepting requests to port 443 or something like that?
What’s the output of these two?
curl -X GET -I http://gempost.opensyscon.com.au
curl -X GET -Ik https://gempost.opensyscon.com.au
Edit:
Wait, I just realized that Apache should not be in the request path if you are configuring HTTPS via your Node application.
If Apache is in the request path on the way to the Node app, then you need to configure Apache with the SSL certificate, rather than your Node app.