Just submit our new app and got IPv6 rejection as well. Here what apple told me:
We were unable to review your app as it crashed on launch. We have attached detailed crash logs to help troubleshoot this issue.
Please revise your app and test it on a device while connected to an IPv6 network (all apps must support IPv6) to ensure it will launch without crashing.
For additional information about supporting IPv6 Networks, please refer to Supporting IPv6 DNS64/NAT64 Networks and Supporting IPv6-only Networks.
For a networking overview, please see About Networking.
For information on how to symbolicate and read a crash log, please see Tech Note TN2151 Understanding and Analyzing Application Crash Reports.
If you have difficulty reproducing this issue, please try testing the workflow described in Testing Workflow with Xcode’s Archive feature.
If you have code-level questions after utilizing the above resources, you may wish to consult with Apple Developer Technical Support. When the DTS engineer follows up with you, please be ready to provide:
- complete details of your rejection issue(s)
- steps to reproduce the issue(s)
- symbolicated crash logs - if your issue results in a crash log