diff --git a/core/admin/mailu/models.py b/core/admin/mailu/models.py
index 42711cf0..b5ba29c0 100644
--- a/core/admin/mailu/models.py
+++ b/core/admin/mailu/models.py
@@ -628,10 +628,10 @@ class Alias(Base, Email):
                 sqlalchemy.and_(cls.domain_name == domain_name,
                     sqlalchemy.or_(
                         sqlalchemy.and_(
-                            cls.wildcard is False,
+                            cls.wildcard == False,
                             cls.localpart == localpart
                         ), sqlalchemy.and_(
-                            cls.wildcard is True,
+                            cls.wildcard == True,
                             sqlalchemy.bindparam('l', localpart).like(cls.localpart)
                         )
                     )
@@ -643,10 +643,10 @@ class Alias(Base, Email):
                 sqlalchemy.and_(cls.domain_name == domain_name,
                     sqlalchemy.or_(
                         sqlalchemy.and_(
-                            cls.wildcard is False,
+                            cls.wildcard == False,
                             sqlalchemy.func.lower(cls.localpart) == localpart_lower
                         ), sqlalchemy.and_(
-                            cls.wildcard is True,
+                            cls.wildcard == True,
                             sqlalchemy.bindparam('l', localpart_lower).like(
                                 sqlalchemy.func.lower(cls.localpart))
                         )
diff --git a/core/admin/mailu/schemas.py b/core/admin/mailu/schemas.py
index 2742edf1..191d01ac 100644
--- a/core/admin/mailu/schemas.py
+++ b/core/admin/mailu/schemas.py
@@ -590,7 +590,7 @@ class DkimKeyField(fields.String):
                 value = value[:pos]
             else:
                 footer = '-----END PRIVATE KEY-----'
-        except ValueError:
+        except ValueError as exc:
             raise ValidationError(f'invalid dkim key {bad_key!r}') from exc
 
         # remove whitespace from key data