That looks like an ssl error, not a docx error. Do they have an old version of openssl installed? Or, if it's windows, an old version of python/pip/windows/anything?
You could install docx in a virtual environment, storing the package locally, and just distribute it along with your program, instead of installing globally on each computer.
You could install docx in a virtual environment, storing the package locally, and just distribute it along with your program, instead of installing globally on each computer.