环境：

1.ubuntu 上 rails server 开启服务，端口 3000

2.nginx 监听 8000 端口，nginx 配置如下

events {
    worker_connections  1024;
}
http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;
    underscores_in_headers on;
    server {
         listen xx.xx.xx.xx:8000;
         root /home/ubuntu/blog/public;
         location / {
             proxy_pass http://xx.xx.xx.xx:3000/;
         }
         location ~ \.(css|js|jpg|png|gif) {
             root /home/ubuntu/blog/public;
         }
    }
}

现象：

1.Microsoft Edge 和 Firefox 访问 xx.xx.xx.xx:8000 提交表单正常

2.Microsoft Edge，Chrome，Firefox 访问 xx.xx.xx.xx:3000 提交表单正常

3.Chrome 访问 xx.xx.xx.xx:8000 提交表单显示 ActionController::InvalidAuthenticityToken

4.Chrome 版本 58.0.3029.110 (64-bit)

5.报错信息 (太长了，截选)：

Processing by SessionsController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"UN2YDS8C5xIt7Wu2RDmOqC7fa5YgSeGOdNG/YTbZIXNH4MH7ZlFhsWmABC44uLO7YvN4cO72T8ecfu5U3v/i2Q==", "session"=>{"email"=>"[email protected]", "password"=>"[FILTERED]", "remember_me"=>"0"}, "commit"=>"Log in"}
Can't verify CSRF token authenticity.
Completed 422 Unprocessable Entity in 1ms (ActiveRecord: 0.0ms)

ActionController::InvalidAuthenticityToken (ActionController::InvalidAuthenticityToken):

actionpack (5.0.2) lib/action_controller/metal/request_forgery_protection.rb:195:in `handle_unverified_request'
actionpack (5.0.2) lib/action_controller/metal/request_forgery_protection.rb:223:in `handle_unverified_request'
actionpack (5.0.2) lib/action_controller/metal/request_forgery_protection.rb:218:in `verify_authenticity_token'
activesupport (5.0.2) lib/active_support/callbacks.rb:382:in `block in make_lambda'
activesupport (5.0.2) lib/active_support/callbacks.rb:169:in `block (2 levels) in halting'
actionpack (5.0.2) lib/abstract_controller/callbacks.rb:12:in `block (2 levels) in <module:Callbacks>'
activesupport (5.0.2) lib/active_support/callbacks.rb:170:in `block in halting'
activesupport (5.0.2) lib/active_support/callbacks.rb:454:in `block in call'

问题： 这现象让人很疑惑，Rails App 应该没问题，nginx 感觉也没问题，只有 Chrome 的请求，经过 nginx，才会有问题，新人求教。