To install SSL on ASTPP server, edit file
vi /etc/nginx/ssl/nginx.crt;
Add your SSL cert on this file. It is good idea to paste your ca-bundle file content after SSL cert, so you have full chain.
vi /etc/nginx/ssl/nginx.key
Add SSL private key.
Now restart Nginx
nginx -s reload
By default if you use non HTTPS link, you get default nginx page. To avoid this, set a redirect by editing file
vi /etc/nginx/sites-enabled/defaul
Add inside default server entry
return 301 https://YOUR_URL-HERE/;
Now restart nginx.
nginx -s reload
See ASTPP