可以在 chrome 的 dev tools 里看下 networks 和 console 的错误输出。然后在 nginx 的配置文件里添加如下配置， nginx -s reload 生效。

add_header Access-Control-Allow-Origin '*' always;
add_header Access-Control-Allow-Methods 'GET, POST, OPTIONS' always;
add_header Access-Control-Allow-Headers 'DNT,X-Mx-ReqToken,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';

if ($request_method = 'OPTIONS') {
        # Tell client that this pre-flight info is valid for 20 days
        add_header 'Access-Control-Max-Age' 1728000;
        add_header 'Content-Type' 'text/plain charset=UTF-8';
        add_header 'Content-Length' 0;
        return 204;
}