Android Question ERROR java.io.IOException: /storage/emulated/0/Download is not a folder.

Hi guys, I'm making an app, on my app I generate a file and save on Download folder and the copy to internal app folder.

I'm sure my function was working fine on past days, but today start to not work.

Relevant Code:
ruta_download="/storage/emulated/0/Download"
File.ListFiles(ruta_download)
[/CODE]

error:
java.io.IOException: /storage/emulated/0/Download is not a folder.

Device: Android 8.1 Oreo