即使已成功安装证书，也无法在nginx上启用SSL

Question

我在nginx服务器上运行了一个站点。我正在尝试启用ssl。我已经下载了证书，并根据本指南提供了以下输出：https://www.digitalocean.com/community/tutorials/how-to-secure-nginx-with-let-s-encrypt-on-ubuntu-16-04。但是当我去https://example.com它不起作用时......我错过了什么？

root@host2:~# certbot certificates

Saving debug log to /var/log/letsencrypt/letsencrypt.log

    -----------------------------------------------------------------------------
    Found the following certs:
      Certificate Name: example.com
        Domains: example.com
        Expiry Date: 2017-11-25 05:49:00+00:00 (VALID: 89 days)
        Certificate Path: /etc/letsencrypt/live/example.com/fullchain.pem
        Private Key Path: /etc/letsencrypt/live/example.com/privkey.pem
    -----------------------------------------------------------------------------

通过不工作，我的意思是当我转到http版本时，该网站加载正常，但当我转到https版本时，它说该网站无法访问。