Publish file locally does not work

Hi, I am running Twine 2.0.11 (the latest and greatest). When I "publish to file" in my client program, I generate a HTML file, which however, I cannot open with my browser [also, Google Chrome has labelled the file as "insecure". However, changing to Safari doesn't make a dent]. When I import said file to twinery.org and "publish to file" from there, I get a valid HTML that I can download and open locally. What am I doing wrong? Many thanks!