My app has failed Apple testing due to not working on an IPv6 only network. I put in some code that would take an IPv4 address and map it to an IPv6 address. When I call my URL with this new address in the line I get "Bad Request - Invalid Hostname HTTP Error 400. The request hostname is invalid." This is still on an IPv4 network but want to make sure the code works on both. What could be wrong? How have people solved this?