当上传文件大于1M时 Access to XMLHttpRequest at 'https://xxxx/upload' from origin 'https://xxxxx' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. 一看，似乎是跨域问题。实际上是Nginx默认限制的最大传输大小。
解决方法： 找到当前域名的nginx配置文件、
sudo su - root
cd /usr/local/nginx/conf.d/gate.conf
添加 client_max_body_size 100M，想配置多大自行设置。
service nginx reload 重启即可
