This week we will be conducting a “brownout” of all misconfigured GitHub Pages sites. If your GitHub Pages site’s DNS is pointed at an out-of-date IP address, we will intermittently serve a warning page in place of your site’s content. We will update our status site before we do so, and normal functionality will resume at the conclusion of the brownout.
If you use a custom domain with GitHub Pages, please verify that your domain’s DNS settings are properly configured to point to the most up-to-date GitHub IP addresses. This will ensure that your site remains available this week and continues to remain available after December 1st, 2014.
For information on how to tell if your site is affected and what to do to fix it, see the original GitHub Pages Legacy IP Deprecation announcement or the setting up a custom domain with GitHub Pages documentation.
Of course, if you have any questions, we’re here to help.