Just ran across a bug in py2exe where it doesn't add passlib automatically and even including passlib in the packages option doesn't help.
See the following code:

from passlib.apps import custom_app_context
print(custom_app_context.hash('1234'))

It runs under python 3.9 with the following pip reqs:

py2exe
passlib==1.7.4

If I package it using the following py2exe script it works in py2exe 0.10.2.1 but it fails with the most recent py2exe version (0.11.1.1):

from distutils.core import setup
import py2exe #@UnusedImport

setup(
    console= [ { "script": "test.py",}, ],
    options = {"py2exe": {
        "packages": ['passlib'],
        "includes":['configparser'],
 } },
)

For some reason only a couple of files are added from passlib instead of the whole package