diff --git a/pytorch_transformers/modeling_utils.py b/pytorch_transformers/modeling_utils.py
index f1501aa8..8ad0f672 100644
--- a/pytorch_transformers/modeling_utils.py
+++ b/pytorch_transformers/modeling_utils.py
@@ -473,7 +473,7 @@ class PreTrainedModel(nn.Module):
         # redirect to the cache, if necessary
         try:
             resolved_archive_file = cached_path(archive_file, cache_dir=cache_dir, force_download=force_download, proxies=proxies)
-        except EnvironmentError:
+        except EnvironmentError as e:
             if pretrained_model_name_or_path in cls.pretrained_model_archive_map:
                 logger.error(
                     "Couldn't reach server at '{}' to download pretrained weights.".format(
@@ -486,7 +486,7 @@ class PreTrainedModel(nn.Module):
                         pretrained_model_name_or_path,
                         ', '.join(cls.pretrained_model_archive_map.keys()),
                         archive_file))
-            return None
+            raise e
         if resolved_archive_file == archive_file:
             logger.info("loading weights file {}".format(archive_file))
         else: