diff --git a/sentry_ldap_auth/backend.py b/sentry_ldap_auth/backend.py
index 5d9ed1c..9798c30 100644
--- a/sentry_ldap_auth/backend.py
+++ b/sentry_ldap_auth/backend.py
@@ -24,11 +24,21 @@ def get_or_create_user(self, username, ldap_user):
         except ImportError:
             pass
         else:
-            userEmail = UserEmail.objects.get(user=user)
+            userEmail = UserEmail.objects.filter(user=user)
             if not userEmail:
                 userEmail = UserEmail.objects.create(user=user)
+            else:
+                userEmail = userEmail[0]
 
-            userEmail.email=ldap_user.attrs.get('mail', ' ')[0] or ''
+            if not hasattr(settings, 'AUTH_LDAP_DEFAULT_EMAIL_DOMAIN'):
+                email = ' '
+            else:
+                email = username + '@' + settings.AUTH_LDAP_DEFAULT_EMAIL_DOMAIN
+
+            if 'mail' in ldap_user.attrs:
+                userEmail.email = ldap_user.attrs.get('mail')[0]
+            else:
+                userEmail.email = email
             userEmail.save()
 
         # Check to see if we need to add the user to an organization