PyQt5 cannot asyn

I would like to create a system tray icon and make it disappear after 15 minutes. But the code stops on the app.exec_() and cannot go into the next line. I try to use the asyn and await function but still fails.

import subprocess
import time
import schedule
import asyncio
import sys
from PyQt5.QtWidgets import QApplication,QSystemTrayIcon,QMenu
from PyQt5.QtGui import QIcon
import os
import distutils.spawn
async def showSystemTrayIcon():
      app=QApplication(sys.argv)
      OnlinetrayIcon = 
      QSystemTrayIcon(QIcon("Desktop/Project/Project/System Tray 
      Icon/Online.PNG"),parent=app)
      OfflinetrayIcon = 
      QSystemTrayIcon(QIcon("Desktop/Project/Project/System Tray 
      Icon/Offline.PNG"),parent=app)
      OnlinetrayIcon.show()
      print("Show Tray Icon") 
      await asyncio.run(app.exec_())
      print("sleep 15") 
      time.sleep(15)
      print("Exit") 
      sys.exit(app.exec_())

asyncio.run(showSystemTrayIcon() )