diff --git a/modoboa/core/tests/test_ldap.py b/modoboa/core/tests/test_ldap.py
index 1e47f9c60..a1b843319 100644
--- a/modoboa/core/tests/test_ldap.py
+++ b/modoboa/core/tests/test_ldap.py
@@ -119,7 +119,7 @@ class LDAPAuthenticationTestCase(LDAPTestCaseMixin, ModoTestCase):
         })
         username = "mailadmin"
         self.authenticate(username, "test", False)
-        self.check_created_user(username, "DomainAdmins", False)
+        self.check_created_user("mailadmin@example.com", "DomainAdmins", False)
 
 
 class ProfileTestCase(LDAPTestCaseMixin, ModoTestCase):
diff --git a/modoboa/lib/authbackends.py b/modoboa/lib/authbackends.py
index a4122b497..34b64641e 100644
--- a/modoboa/lib/authbackends.py
+++ b/modoboa/lib/authbackends.py
@@ -92,9 +92,13 @@ try:
                     if attr in ldap_user.attrs:
                         email = ldap_user.attrs[attr][0]
                         break
-                if email is None and group == "SimpleUsers":
-                    return None
-                username = email
+                if email is None:
+                    if group == "SimpleUsers":
+                        # Only DomainAdmins can have a username which
+                        # is not an email address
+                        return None
+                else:
+                    username = email
             user, created = User.objects.get_or_create(
                 username__iexact=username,
                 defaults={