Sorry for the issue and for not answering you sooner.
Could you let us know if you saw an error message? Can you share a screenshot of it? Did you try using another browser to see if that would help? Is it happening with every project, and what type of project did you try to download?
We suggest signing out, clearing the caches and cookies, and signing in. Do you see any difference? You can try to download your file from another browser, such as Safari or Google Chrome.