Error in running with astropy module

[NIcola Montecchiari]

Dear All,

I have got an application which uses astropy. I am getting at run time the following error:

ImportError: Astropy requires the 'six' module of minimum version 1.10; normally
 this is bundled with the astropy package so if you get this warning consult the
 packager of your Astropy distribution.

I'm using python 2.7 32-bit with the following freeze:

altgraph==0.16.1
astropy==2.0.14
atomicwrites==1.3.0
attrs==19.2.0
auto-py-to-exe==2.6.5
bottle==0.12.17
bottle-websocket==0.2.9
certifi==2019.9.11
cffi==1.12.3
chardet==3.0.4
colorama==0.4.1
dis3==0.1.3
Eel==0.10.4
funcsigs==1.0.2
future==0.17.1
gevent==1.4.0
gevent-websocket==0.10.1
greenlet==0.4.15
idna==2.8
iso8601==0.1.12
macholib==1.11
modulegraph==0.17
more-itertools==5.0.0
numpy==1.16.5
pefile==2019.4.18
pluggy==0.7.1
psutil==5.6.3
py==1.8.0
pycparser==2.19
pyfits==3.5
PyInstaller==3.5
PyPubSub==3.3.0
pytest==3.6.4
pywin32==225
pywin32-ctypes==0.2.0
PyYAML==5.1.2
requests==2.22.0
serial==0.0.97
six==1.12.0
urllib3==1.25.6
whichcraft==0.6.1

Does anybody know how to fix this? I googled around but the answers I found weren't fixing it.

Thank you and best regards

Nicola