Somebody who works FileProvider?

I have problem with FileProvider = error:
Attempt to invoke virtual method 'android.content.res.XmlResourceParser android.content.pm.PackageItemInfo.loadXmlMetaData(android.content.pm.PackageManager, java.lang.String)' on a null object reference

Manifest:

FileProvider in *.cs file:
var folderPath = new Java.IO.File(Forms.Context.FilesDir, "dwnlds/");
if (!folderPath.Exists())
folderPath.Mkdirs();

var filePath = new Java.IO.File(folderPath, filename);
Android.Net.Uri contentUri = FileProvider.GetUriForFile(Forms.Context, "com.ladis.smartapps.provider", filePath);

Any ideas how to help me?