网站不能安装ssl证书有什么风险

<!-- 不安全的HTTP连接 -->
<form action="http://example.com/submit" method="post">
  <input type="text" name="credit_card" />
  <input type="submit" value="Submit" />
</form>

<!-- 安全的HTTPS连接 -->
<form action="https://example.com/submit" method="post">
  <input type="text" name="credit_card" />
  <input type="submit" value="Submit" />
</form>

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

server {
    listen 443 ssl;
    server_name example.com;

    ssl_certificate /path/to/certificate.crt;
    ssl_certificate_key /path/to/private.key;

    location / {
        # 配置网站内容
    }
}