diff --git a/src/aeat/rest_framework/serializers.py b/src/aeat/rest_framework/serializers.py
index 25acd2b..222e14d 100644
--- a/src/aeat/rest_framework/serializers.py
+++ b/src/aeat/rest_framework/serializers.py
@@ -91,7 +91,7 @@ def get_class_for_aeat_response(data):
 
     return {
         f'{ens}IE328V4Sal.xsd': ENSSerializer,
-        f'{exs}IE304V4Sal.xsd': ENSSerializer,
+        f'{ens}IE304V4Sal.xsd': ENSSerializer,
         f'{ens}IE316V4Sal.xsd': ENSFunctionalErrorSerializer,
         f'{exs}IE628V1Sal.xsd': EXSSerializer,
     }.get(xsd, UnknownResponseSerializer)