Hi.
Found the solution with the below code:
var server = new DirectoryEntry(string.Format("WinNT://{0},Computer", machine));
DirectoryEntry group = server.Children.Cast<DirectoryEntry>().Where(
d => d.SchemaClassName.Equals("Group") && d.Name.Equals("Group Name")
).Single<DirectoryEntry>();
Got from: https://stackoverflow.com/questions/25060655/c-sharp-principalcontext-the-network-path-was-not-found
Thanks