diff --git a/rsconcept/backend/apps/rsform/tests/s_views/t_rsforms.py b/rsconcept/backend/apps/rsform/tests/s_views/t_rsforms.py
index bd214c8b..ca674801 100644
--- a/rsconcept/backend/apps/rsform/tests/s_views/t_rsforms.py
+++ b/rsconcept/backend/apps/rsform/tests/s_views/t_rsforms.py
@@ -219,6 +219,15 @@ class TestRSFormViewset(EndpointTester):
         self.assertEqual(x4.term_raw, data['term_raw'])
         self.assertEqual(x4.term_forms, data['term_forms'])
 
+        data = {
+            'alias': 'X5',
+            'cst_type': CstType.BASE,
+            'insert_after': None,
+            'term_raw': 'test5'
+        }
+        response = self.executeCreated(data=data, item=self.owned_id)
+        self.assertEqual(response.data['new_cst']['alias'], data['alias'])
+
 
     @decl_endpoint('/api/rsforms/{item}/cst-rename', method='patch')
     def test_rename_constituenta(self):
diff --git a/rsconcept/backend/apps/rsform/views/rsforms.py b/rsconcept/backend/apps/rsform/views/rsforms.py
index ff96708e..abdb28dc 100644
--- a/rsconcept/backend/apps/rsform/views/rsforms.py
+++ b/rsconcept/backend/apps/rsform/views/rsforms.py
@@ -72,7 +72,7 @@ class RSFormViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retr
         serializer = s.CstCreateSerializer(data=request.data)
         serializer.is_valid(raise_exception=True)
         data = serializer.validated_data
-        if 'insert_after' in data:
+        if 'insert_after' in data and data['insert_after'] is not None:
             try:
                 insert_after = m.Constituenta.objects.get(pk=data['insert_after'])
             except m.LibraryItem.DoesNotExist: