I have facing problem
Additionally, we discovered one or more bugs in your app when reviewed on iPad and iPhone running iOS 11.1.1 on Wi-Fi connected to an IPv6 network.
Specifically, we were unable to login using Facebook.
For a networking overview, please review About Networking. For a more specific overview of App Review’s IPv6 requirements, please review the IPv6 and App Review discussion on the Apple Developer Forum.
That we can't reproduce it, so we do not have idea how to solve it. Please help me.