diff --git a/lib/workload_service/handlers/task_completed_handler.ex b/lib/workload_service/handlers/task_completed_handler.ex
index 6c43149..cf388c3 100644
--- a/lib/workload_service/handlers/task_completed_handler.ex
+++ b/lib/workload_service/handlers/task_completed_handler.ex
@@ -30,7 +30,7 @@ defmodule WorkloadService.Handlers.TaskCompletedHandler do
         case Aggregate.aggregate_state(
                WorkloadService.CommandedApp,
                module,
-               event.id
+               to_string(event.id)
              ) do
           nil ->
             Logger.warning("TaskCompletedHandler: aggregate not found for #{event.id}")