Dropbox can support it, but you need a little more than just dl=1.
The thing is that usual Dropbox links ("get dropbox link" thing) generate links to Dropbox page, not the file.
You can alter the link to aim it to file server directly, instead.
This is done by this change, here is original link:
And here is the link you need. Be aware it leads to totally another server, which has no HTML content, so you access the files directly:
As you can see, the alternating of the start of URL does the thing.
dl=1 , the thing is, that for some files it can do difference if it starts to download or it shows in browser. So pictures etc. with
dl=0 will just show in browser, but with
dl=1 they are forced to download.
You need the server to directly download the file and not comunicate it with HTML nor show the file, so you need to change the
dl=1, too. (However it could probably work with
?dl=0 totally deleted or with keeping =0, too, because ZIP file is not the type to be shown in browser, so it downloads anyway).
NOTE: Do not change the string identifying the file and user in between.