My iOS app uses a TCP/IP Socket (IPv4/IPv6) to establish a connection between the app itself and a server in the internet. It works well on all test devices. But in the apple app review, the app gets rejected in iTunesConnect, because the outgoing connection is blocked on the test device from apple. I cant reproduce the error. The socket cant't just connect to the server. It works in a IPv6 only network.
It is necessary, to whitelist somewhere the DNS/IP from the server, to allow a outgoing connection?