I currently can't export anything in the grids for products, clients and newsletters in my computer (and from another computer in another state). It downloads properly from my phone.
When I click the export from the grid, the files starts to download but takes a long time waiting and finally fails: https://imgur.com/a/u3pzU
After failing, I can see in the network tab of the browsers webdev toolbar the request, and if I export it as a .har, it shows that the file's contents where downloaded.
This fails in Edge, Chrome and FF.