Deployment with HTTPS/SSL on Nginx not working

[steph-koopmanschap]

Nginx was setup as a reverse-proxy on ubuntu-server in VirtualBox in NAT network mode.
A static DNS was created in the network router mapping the domain jasmaserver.lan to the IP 192.168.254.151 which is the ubuntu-server machine in VirtualBox.
After creating a self-signed SSL certificate. The jasmaHTTPS.conf file was copied to /etc/nginx/sites-available and symlinked, and Nginx restarted.

When trying to reach https://jasmaserver.lan or https://192.168.254.151 in the browser nginx gave a 502 Bad Gateway response.
But when visiting http://jasmaserver.lan:3000 the jasma app loads up correctly without problems.
The command tail -f /var/log/nginx/error.log gave the following result:

2023/02/08 09:31:14 [error] 7830#7830: *1 SSL_do_handshake() failed (SSL: error:0A00010B:SSL routines::wrong version number) while SSL handshaking to upstream, client: 192.168.254.103, server: jasmaserver.lan, request: "GET / HTTP/1.1", upstream: "https://127.0.0.1:3000/", host: "192.168.254.151"

The ports 80, 443, 3000, and 5000 were open on the server.

The Node processes on ports 3000 and 5000 do not use HTTPS/SSL.
The nginx reverse proxy uses https.
So the proxy is from HTTPS to HTTP.