Error while downloading file from Firebase Storage

[haqqi-zk]

I tried to use this package to download certain file from firebase storage using the DownloadHandlerFile request function but always meet with the same error

Proyecto26.RequestException: HTTP/1.1 403 Forbidden

and here is the code

i am using .pdf file as an example and the url target from the request debug has no problem when accessed
i also already make the storage rules open at the firebase

when i tried to download the file without the "?alt=media" word to it it can download but not the real file but only the file with several value in it

which is not the one i want
if there is something i missed in the script please tell me
its hard because there is no real demo about DownloadHandlerFile for REST API
Thank you