diff --git a/django/contrib/admin/sites.py b/django/contrib/admin/sites.py
index 4446490451..1778ae40b5 100644
--- a/django/contrib/admin/sites.py
+++ b/django/contrib/admin/sites.py
@@ -327,13 +327,11 @@ class AdminSite(object):
                 try:
                     user = User.objects.get(email=username)
                 except (User.DoesNotExist, User.MultipleObjectsReturned):
-                    message = _("Usernames cannot contain the '@' character.")
+                    pass
                 else:
                     if user.check_password(password):
                         message = _("Your e-mail address is not your username."
                                     " Try '%s' instead.") % user.username
-                    else:
-                        message = _("Usernames cannot contain the '@' character.")
             return self.display_login_form(request, message)
 
         # The user data is correct; log in the user in and continue.
diff --git a/django/contrib/admin/views/decorators.py b/django/contrib/admin/views/decorators.py
index afdc07589d..82184fc9d3 100644
--- a/django/contrib/admin/views/decorators.py
+++ b/django/contrib/admin/views/decorators.py
@@ -60,10 +60,6 @@ def staff_member_required(view_func):
                 users = list(User.objects.filter(email=username))
                 if len(users) == 1 and users[0].check_password(password):
                     message = _("Your e-mail address is not your username. Try '%s' instead.") % users[0].username
-                else:
-                    # Either we cannot find the user, or if more than 1
-                    # we cannot guess which user is the correct one.
-                    message = _("Usernames cannot contain the '@' character.")
             return _display_login_form(request, message)
 
         # The user data is correct; log in the user in and continue.
diff --git a/tests/regressiontests/admin_views/tests.py b/tests/regressiontests/admin_views/tests.py
index 8fea95bf6a..f5da6b017e 100644
--- a/tests/regressiontests/admin_views/tests.py
+++ b/tests/regressiontests/admin_views/tests.py
@@ -453,12 +453,12 @@ class AdminViewPermissionsTest(TestCase):
         self.assertContains(login, "Your e-mail address is not your username")
         # only correct passwords get a username hint
         login = self.client.post('/test_admin/admin/', self.super_email_bad_login)
-        self.assertContains(login, "Usernames cannot contain the '@' character")
+        self.assertContains(login, "Please enter a correct username and password")
         new_user = User(username='jondoe', password='secret', email='super@example.com')
         new_user.save()
         # check to ensure if there are multiple e-mail addresses a user doesn't get a 500
         login = self.client.post('/test_admin/admin/', self.super_email_login)
-        self.assertContains(login, "Usernames cannot contain the '@' character")
+        self.assertContains(login, "Please enter a correct username and password")
 
         # Add User
         request = self.client.get('/test_admin/admin/')
@@ -962,12 +962,12 @@ class SecureViewTest(TestCase):
         self.assertContains(login, "Your e-mail address is not your username")
         # only correct passwords get a username hint
         login = self.client.post('/test_admin/admin/secure-view/', self.super_email_bad_login)
-        self.assertContains(login, "Usernames cannot contain the '@' character")
+        self.assertContains(login, "Please enter a correct username and password")
         new_user = User(username='jondoe', password='secret', email='super@example.com')
         new_user.save()
         # check to ensure if there are multiple e-mail addresses a user doesn't get a 500
         login = self.client.post('/test_admin/admin/secure-view/', self.super_email_login)
-        self.assertContains(login, "Usernames cannot contain the '@' character")
+        self.assertContains(login, "Please enter a correct username and password")
 
         # Add User
         request = self.client.get('/test_admin/admin/secure-view/')