edit calling created_by method in marketing controller

app/Http/Controllers/DS/MarketingController.php

@@ -1638,7 +1638,7 @@ class MarketingController extends Controller
 			$product = $product->package_name;
 		}
 
-		$created_by = Staff::with('StaffDetail')->find($wo->created_by)->first(); 
+		$created_by = Staff::with('StaffDetail')->where("_id",$wo->created_by)->first();
 		if(empty($created_by)){
 			$created_by = '';
 		}