nginx配置文件：
server { listen 80; listen 443; server_name www.xxx.com; #charset koi8-r; #access_log /var/log/nginx/host.access.log main; ssl on; root html; index index.html index.htm; ssl_certificate /etc/nginx/conf.d/cert/214567143360012.pem; ssl_certificate_key /etc/nginx/conf.d/cert/214567143360012.key; ssl_session_timeout 5m; ssl_ciphers ECDHE-RSA-AES128-GCM-SHA256:ECDHE:ECDH:AES:HIGH:!NULL:!aNULL:!MD5:!ADH:!RC4; ssl_protocols TLSv1 TLSv1.1 TLSv1.2; ssl_prefer_server_ciphers on;} 访问https时候正常，不过访问http的时候会出现
The plain HTTP request was sent to HTTPS port错误直译下来就是：普通HTTP请求发送到HTTPS端口。
参考官方文档解决方法如下：
server { listen 80; listen 443 ssl; server_name www.xxx.com; #charset koi8-r; #access_log /var/log/nginx/host.access.log main; root html; index index.html index.htm; ssl_certificate /etc/nginx/conf.d/cert/214567143360012.pem; ssl_certificate_key /etc/nginx/conf.d/cert/214567143360012.key; ssl_session_timeout 5m; ssl_ciphers ECDHE-RSA-AES128-GCM-SHA256:ECDHE:ECDH:AES:HIGH:!NULL:!aNULL:!MD5:!ADH:!RC4; ssl_protocols TLSv1 TLSv1.1 TLSv1.2; ssl_prefer_server_ciphers on;} 删掉ssl on; 并在 listen 443; 443后加上ssl即可