diff --git a/modoboa/core/templates/settings.py b/modoboa/core/templates/settings.py
index af94907df..51dae7c3b 100644
--- a/modoboa/core/templates/settings.py
+++ b/modoboa/core/templates/settings.py
@@ -159,6 +159,8 @@ AUTHENTICATION_BACKENDS = (
     'modoboa.lib.authbackends.SimpleBackend',
 )
 
+SESSION_COOKIE_AGE = 600
+
 # A sample logging configuration. The only tangible logging
 # performed by this configuration is to send an email to
 # the site admins on every HTTP 500 error when DEBUG=False.
diff --git a/modoboa/lib/templatetags/libextras.py b/modoboa/lib/templatetags/libextras.py
index 315bb39de..95710150a 100644
--- a/modoboa/lib/templatetags/libextras.py
+++ b/modoboa/lib/templatetags/libextras.py
@@ -193,7 +193,12 @@ class ConnectedUsers(template.Node):
                 uid_list.append(uid)
 
         # Query all logged in users based on id list
-        context[self.varname] = [User.objects.get(pk=uid) for uid in uid_list]
+        context[self.varname] = []
+        for uid in uid_list:
+            try:
+                context[self.varname].append(User.objects.get(pk=uid))
+            except User.DoesNotExist:
+                print "unknown user"
         return ''
 
 @register.tag