先看看iOS9新特性中关于ATS的官方文档：
App Transport Security
App Transport Security (ATS) enforces best practices in the secure connections between an app and its back end. ATS prevents accidental disclosure, provides secure default behavior, and is easy to adopt; it is also on by default in iOS 9 and OS X v10.11. You should adopt ATS as soon as possible, regardless of whether you’re creating a new app or updating an existing one.
If you’re developing a new app, you should use HTTPS exclusively. If you have an existing app, you should use HTTPS as much as you can right now, and create a plan for migrating the rest of your app as soon as possible. In addition, your communication through higher-level APIs needs to be encrypted using TLS version 1.2 with forward secrecy. If you try to make a connection that doesn‘t follow this requirement, an error is thrown. If your app needs to make a request to an insecure domain, you have to specify this domain in your app‘s Info.plist file.
再看看控制台打印
Application Transport Security has blocked a cleartext HTTP (http://) resource load since it is insecure. Temporary exceptions can be configured via your app‘s Info.plist file.
最后根据提示配置项目的info.plist文件
OK!
原文：http://www.cnblogs.com/mysticCoder/p/5103401.html