问题：XMLHttpRequest cannot load http://192.168.1.4:9010//api/contacts. The ‘Access-Control-Allow-Origin‘ header contains the invalid value ‘1‘. Origin ‘http://192.168.1.4:9011‘ is therefore not allowed access.
解决：IIS 配置 就可以了, 选中站点后选择 Http 响应头 ,右侧选择添加,
Access-Control-Allow-Origin , 值设置
Ajax 请求请求 MVC WebAPI跨域问题；XMLHttpRequest cannot load
原文：https://www.cnblogs.com/-hao/p/9500913.html