In our site we have links which enable the users to download PDF and MS Word files. The PDF format works fine. The MS Word docx format is being downloaded as a zip file. What do I have to do to enable the MS Word docx format to be downloaded correctly - as a docx file?

The issue is - the MS Word extension docx is being changed to zip. If I change the downloaded file extension from zip to docx, the file opens correctly in MS Word.

Thank you in advance for any tips.