Unable to exeize tkinterdnd

Now that the code for editing the PDF is complete, we are trying to exe in the virtual environment of venv.
The problem is that exe results in an exception and the tkdnd package is not found.

I did pip install tkinterdnd2 before exe, so it should have been installed...
Please let me know how to solve this problem.

The operating system is Windows 10 home
The python version is 3.9.5 64-bit
Imported on app.py is

import tkinter
from tkinterdnd2 import DND_FILES, TkinterDnD
import tkinter.filedialog
from PIL import ImageTk
from PyPDF2 import PdfFileMerger, PdfFileReader, PdfFileWriter
from pdf2 image import convert_from_path
import tkinter.messagebox asmb

The pip list for the virtual environment is

 altgraph
future
pdf2 image
pefile
Pillow
pip
pyinstaller
pyinstaller-hooks-contrib
PyPDF2
pywin32-ctypes
setupools
tkinterdnd2
typing_extensions

Yes.
The screen when starting the exe file is shown below.
Thank you.