diff --git a/vall_e/engines/base.py b/vall_e/engines/base.py
index 6d3a871..ae20ad8 100755
--- a/vall_e/engines/base.py
+++ b/vall_e/engines/base.py
@@ -493,10 +493,11 @@ class Engines(dict[str, Engine]):
 			total_elapsed_time += elapsed_time
 			grad_norm = engine.get_global_grad_norm()
 			loss_scale = 1
-			if hasattr(engine.optimizer, "loss_scale"):
+			if hasattr(engine.optimizer, "loss_scale") and engine.optimizer.loss_scale is not None:
 				loss_scale = engine.optimizer.loss_scale
 			
-			grad_norm /= loss_scale
+			if grad_norm is not None:
+				grad_norm /= loss_scale
 
 			stats.update(
 				flatten_dict(