diff --git a/modoboa/admin/forms/domain.py b/modoboa/admin/forms/domain.py
index d1549a4cf..d08d2563e 100644
--- a/modoboa/admin/forms/domain.py
+++ b/modoboa/admin/forms/domain.py
@@ -376,7 +376,7 @@ class DomainForm(TabForms):
         """
         if "general" in self.instances:
             self.instances["general"].oldname = self.instances["general"].name
-            self.instances["general"].old_dkim_key_length  = self.instances["general"].dkim_key_length
+            self.instances["general"].old_dkim_key_length = self.instances["general"].dkim_key_length
         return super(DomainForm, self).is_valid()
 
     def save(self):
diff --git a/modoboa/admin/models/domain.py b/modoboa/admin/models/domain.py
index 5d14044ba..1d9534423 100644
--- a/modoboa/admin/models/domain.py
+++ b/modoboa/admin/models/domain.py
@@ -87,6 +87,7 @@ class Domain(AdminObject):
         super(Domain, self).__init__(*args, **kwargs)
         self.old_mail_homes = None
         self.oldname = self.name
+        self.old_dkim_key_length = self.dkim_key_length
 
     @property
     def domainalias_count(self):
diff --git a/modoboa/admin/tests/test_domain.py b/modoboa/admin/tests/test_domain.py
index 167fd43d4..81c673dcd 100644
--- a/modoboa/admin/tests/test_domain.py
+++ b/modoboa/admin/tests/test_domain.py
@@ -452,4 +452,5 @@ class DKIMTestCase(ModoTestCase):
         self.assertEqual(dom.dkim_private_key_path, "")
         os.unlink(key_path)
         call_command("modo", "manage_dkim_keys")
-        self.assertTrue(os.path.exists(key_path))
\ No newline at end of file
+        self.assertTrue(os.path.exists(key_path))
+        
\ No newline at end of file