重复出现此错误：

$ bundle exec jekyll serve
Configuration file: /Users/dmitrizaitsev/Repos/publishing-reform.gitlab.io/_config.yml
Configuration file: /Users/dmitrizaitsev/Repos/publishing-reform.gitlab.io/_config.yml
            Source: /Users/dmitrizaitsev/Repos/publishing-reform.gitlab.io
       Destination: /Users/dmitrizaitsev/Repos/publishing-reform.gitlab.io/_site
 Incremental build: disabled. Enable with --incremental
      Generating... 
                    done in 0.344 seconds.
 Auto-regeneration: enabled for '/Users/dmitrizaitsev/Repos/publishing-reform.gitlab.io'
Configuration file: /Users/dmitrizaitsev/Repos/publishing-reform.gitlab.io/_config.yml
    Server address: http://127.0.0.1:4000//
  Server running... press ctrl-c to stop.
[2018-04-27 12:36:29] ERROR `/socket.io/' not found.
[2018-04-27 12:36:29] ERROR `/socket.io/' not found.
[2018-04-27 12:36:34] ERROR `/socket.io/' not found.
   ... repeating this error message again and again ...

出现这种情况的任何原因以及任何摆脱此消息的方法？

部署的站点似乎运行没有问题：https://publishing-reform.gitlab.io/

文件 _config.yml ：

# Site settings
title: Publishing Reform
baseurl: "/" # the subpath of your site, e.g. /blog
url: "" # the base hostname & protocol for your site

# Build settings
markdown: kramdown
exclude: ["README.md"]
socket.io gitlab jekyll