I got the same issue. All downloads are showing „access denied“ in the file Browser overview. Also I keep getting a 500 server error if I try to access the „all packages“ page. It seems that the plugin has no access to the files folder on the ftp anymore. However, nothing seems to have changed. Write/read access still the same.
I also tried to roll back to an older Version of the download pro plugin. Still the same, so I guess it‘s caused by a WordPress update or something like that.
Thank you,
Andreas