netP5 (TCP/IP networking under android)

netP5 problem: The code below only works with the delay, otherwise the Client.send() operation throws a null pointer exception. Should I check/wait for something after creating a client?

Client = new TcpClient(Listener, IP, 23, TcpServer.MODE_NEWLINE);
    
delay(1000);
    
Client.send("MC@\r");

No exception with MODE_STREAM - but with MODE_STREAM, the listener (implemented a per example from Andreas in this topic: https://forum.processing.org/one/topic/networking-between-android-and-server-connectbot-type-of-thing#25080000001863165.html) receives no data from the addressed mircocontroller, which sends \r\n-terminated strings. I donät really know what streams are.