Could you please provide more details? Which format are you donwloading (mp4/pdf/png/jpg)? A screenshot showing the error as well as the browser's address bar would help.
Ok, but I am due to send this to my publisher and it has to be in PDF format... Even downloading images and then creating a PDF via quick actions means I am loosing some of the quality - especially font wise when it's printed. This is very important for my business