You could be missing a lot of things. Do you have a certificate?
Note: The common (best?) practice is to use a proxy, something like nginx in front of your application for things like TLS, rate limiting, forwarding, etc.
Yes, I do have a certificate (I am using Let's encrypt) and https://www.mywebsite.com works just fine. However if I put simply www.rateneighbor.com, it does not automatically redirect to https and it serves from plain http
I am using clever-cloud.com as PaaS provider and as per them ‘’ You just have to check the standard proxy HTTP headers’’.