I would add the NS to your Local intranet sites, or if you're accessing it remotely, add it to Trusted Sites.
In IE, Tools > Internet Options, Security Tab, select Trusted Sites, click Sites, in the first blank, type your server name (e.g. altiriserver.mycompany.com) and click Add. If you're not using SSL (typical), uncheck 'Require server verification (https:) for all sites in this zone, then click Close.
Close all IE instances and then reopen and try again.