If you are experiencing difficulty with accessing any aspect of your course site from lagunita.stanford.edu due to a warning message that displays in your browser, it could be that your browser's firewall settings are preventing this access.
First check if you have any security software (such as Avast!) enabled on your computer. If so, this software may not be recognizing the Stanford Online course content. To fix this, change your firewall settings to allow access to the following domains: