The plain HTTP request was sent to HTTPS port

I have the next NGINX proxy configuration

http {
    server_tokens off;
server {
    listen     7443 ssl;
    ssl_certificate     /etc/nginx/ssl/star.crt;
    ssl_certificate_key /etc/nginx/ssl/star.key;
    location /prometheus/ {
      auth_basic           "Prometheus";
      auth_basic_user_file /etc/nginx/.htpasswd;
      proxy_set_header Host $host;
      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      # I leave this hardcoded for now
      proxy_pass http://prometheus:9090/prometheus/;
   }

    location / {
      auth_basic           "Prometheus";
      auth_basic_user_file /etc/nginx/.htpasswd;
      proxy_set_header Host $host;
      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      # I leave this hardcoded for now
      proxy_pass http://alertmanager:9093;
   }
 }
}
events {}

If I enter in browser URL without specification of HTTPS by using port 7443, I get:

The plain HTTP request was sent to HTTPS port

For example: prometheus.example.com:7443/prometheus/ or prometheus.example.com:7443/#/alerts/

How can I make NGINX redirect to HTTPS automatically if I specify such URLs without HTTPS?