File Access Permission

Hi,
I want read a file in external storage with mi app, I request storage permission:

if (!(await CrossPermissions.Current.CheckPermissionStatusAsync<StoragePermission>()).Equals(PermissionStatus.Granted)) { if(await CrossPermissions.Current.RequestPermissionsAsync(Permission.Storage))[Permission.Storage].Equals(PermissionStatus.Granted)) { return true; } else { return false; } }

This message apparence:

Not say "files" like this:

So for that when i try read file, UnauthorizedException is invoked.

¿Any solution?

Thanks.