linux - nginx redirect http to https not working

I am trying to reroute from http to https. For example you visit example.com and you will be automatically redirected to https://example.com.

I tryed using this one:

server {
      listen         80;
      return 301 https://$host$request_uri;
} 

as well as this one:

server {
      listen         80;
      server_name    example.com;
      return         301 https://$server_name$request_uri;
}

as found here : In Nginx, how can I rewrite all http requests to https while maintaining sub-domain?

But neither of seem are wokring for me. I am staying on example.com.

Anyone got an idea?