SharePoint服务器安装在一个VM里面，使用IP去访问SharePoint Central Administration是成功的，但是访问其他的site就会显示401 unauthorized。
solution：
deactivate Minimal Download Strategy Feature in site settings
https://social.technet.microsoft.com/Forums/ie/en-US/dbd7563e-52e7-4456-9102-74c9e4766646/can-not-access-sharepoint-2013-site-i-am-getting-401-unauthorized
Go to site –> Site settings –>Manage site features–> Deactivate Minimal Download Strategy