If you have configured your Smoothwall Filter and Firewall to use the Web Cache Communication Protocol (WCCP), see our help topic, Configuring the Web Cache Communication Protocol (WCCP) and to use an SSL login page, see our help topic, Customizing the SSL Login Page, you might encounter issues if you have missing DNS entries or if your DNS entries are not up to date.
It's a WCCP requirement that devices can properly resolve the Smoothwall Filter and Firewall host name via the DNS. Therefore, we recommend that you check that your DNS entries are up to date.