Xamarin Forms. Android. How to properly organize access to the socket server?

Question

client-server

Good afternoon. I am developing in Xamarin Forms for Android. I'm trying to raise a socket server on a smartphone. The client is a console application.
I get the address of the server (smartphone) as follows:

IPAddress[] adresses = Dns.GetHostAddresses(Dns.GetHostName());
if (adresses != null && adresses[0] != null)
{
      adr = adresses[0].ToString();
}
strendpoint = adr + ":2780";
IPEndPoint localEndPoint = CreateIPEndPoint(strendpoint);
_server = new TcpListenerServer(localEndPoint);

Then I go to 2ip.ru from my smartphone, find out my IP and drive it into the client:

const int port = 2780;
const string address = "85.26.233.137";
client = new TcpClient(address, port);
NetworkStream stream = client.GetStream();

So. The client thus cannot reach the server. If I connect my smartphone to my home Wi-Fi (that is, both the server and the client are now on the same network), and its address becomes something like 192.168.0.105, then the client can connect to this address.
I noticed that the address that 2ip.ru gives out when I work through an operator (Megafon) differs from the address that is indicated in the phone parameters in the "About the device" section - there it is 100.99.225.236. But the client cannot reach this address either. Can you please tell me how to organize this system?