Copied/shared Dropbox link does not open an Index.html file

Does anybody know why a copied/shared Dropbox link does not open an 'Index.html' file within a folder.

Index.html is the main file in a folder which opens up the main page in a small website for example. I used to achieve the required result through Dropbox about 5 years ago in my previous job, simply by sharing the 'Index.html' file and then every other page within the same folder operates through the browser in the same way like using a mini website. Now in this current instance I have a folder containing an entire e-Learning module, but opening copied/shared Dropbox link to this index file displays nothing at all in the browser (it displays a blank page in our default Microsoft Edge, I also tried Chrome with same result). I tried setting up a share on the folder containing all the files (which I never needed to do previously) but that didn't change the result. If I click on the index file locally from my desktop it opens my default browser and works perfectly. Why does it not work through the Dropbox link when taken to 'Index.html', since I am doing nothing differently to how I used to achieve this previously? Can anyone assist?