问题：
Guideline 2.1 - Performance
Thank you for your resubmission. However, we discovered one or more bugs in your app when reviewed on iPhone running iOS 10.3.1 on Wi-Fi connected to an IPv6 network.
Specifically, your Login button is unresponsive and we are unable to sign in.
Please see attached screenshots for details.
Next Steps
To resolve this issue, please run your app on a device while connected to an IPv6 network (all apps must support IPv6) to identify any issues, then revise and resubmit your app for review.
If we misunderstood the intended behavior of your app, please reply to this message in Resolution Center to provide information on how these features were intended to work.
For new apps, uninstall all previous versions of your app from a device, then install and follow the steps to reproduce the issue. For updates, install the new version as an update to the previous version, then follow the steps to reproduce the issue.
Resources
For information about supporting IPv6 Networks, please review Supporting IPv6 DNS64/NAT64 Networks and About Networking.
解决方法 ①：http://mp.weixin.qq.com/s?plg_nld=1&plg_uin=1&mid=2247483863&idx=1&plg_nld=1&scene=23&plg_auth=1&__biz=MzI0NTI4ODA2Mw%3D%3D&plg_dev=1&srcid=0701GkquSx0l7Z6CchTAHFFn&plg_usr=1&plg_vkey=1&sn=622478d2775c5f8835fe1ed16964552e#rd
解决方法 ②：http://www.cnblogs.com/cudong/p/6524115.html
解决方法 ③：http://www.cnblogs.com/cudong/p/6554779.html