ESP8266 - One server sending data to multiple clients
Your server doesn't handle clients. It is only a listening TCP socket. You must handle incoming TCP connections by checking if the server has a client available.

This is from ChatServer example. A telnet server to connect to with telnet terminal.

void loop() {
  // wait for a new client:
  WiFiClient client = server.available();

  // when the client sends the first byte, say hello:
  if (client) {
    if (client.connected()) {
      if (!alreadyConnected) {
        Serial.println("We have a new client");
        client.println("Hello, client!");
        alreadyConnected = true;
      }

      if (client.available() &gt; 0) {
        // read the byte incoming from the client:
        char c = client.read();
        // echo the byte back to the client:
        client.write(c);
        // echo the byte to the server as well:
        Serial.write(c);
      }
    } else {
      alreadyConnected = false;
      client.disconnect();
    }
  }
}