Error when explorer.exe is not working

[DZX66]

When I use show_toast() when explorer.exe is not working, it catches:
Traceback (most recent call last):
File "schoolpctool.py", line 567, in toaster
File "win10toast_init_.py", line 146, in show_toast
File "win10toast_init_.py", line 123, in _show_toast
pywintypes.error: (-2147467259, 'Shell_NotifyIcon', 'Unspecified error')

After I restart explorer.exe and use show_toast(), it catches:
Traceback (most recent call last):
File "schoolpctool.py", line 567, in toaster
File "win10toast_init_.py", line 146, in show_toast
File "win10toast_init_.py", line 104, in _show_toast
pywintypes.error: (1400, 'UpdateWindow', 'Invalid window handle')

How do I fix it, making it working when explorer.exe is running after it has crushed?