in GXSerial data is not receiving at port

import gurux_dlms
import gurux_common
import gurux_serial
import gurux_net
from gurux_dlms import*
from gurux_common import*
from gurux_serial import*
from gurux_net import*
import serial
import time

client = GXDLMSClient()
client.useLogicalNameReferencing = True

client.clientAddress = 16
client.serverAddress = 1

media = GXSerial(port="COM12")
media.baudRate = 9600
media.open()
#media.addListner(self)
media.getSynchronous()
p = ReceiveParameters()
p.eop = '\n'
p.waitTime = 1000
media.send("Hello!")
time.sleep(2)
media.receive(p)
ret = p.reply
print(ret)

media.close()