Sometimes what you see on your screen, might not be a true representation of what's actively happening on the site.
Example. The background of a web-page might change from blue to red, but when you view it, it still looks blue.
This is because your browser is using a cached version of the web-page, which assists it in loading pages faster, by "remembering" elements of the page the last time you visited. Unfortunately, sometimes your browser will also cache (remember) elements of the site, which were broken (even if it was only offline for a moment).
When you encounter issues with the site, try clearing the cache / temporary files in your web browser, first.
There is a helpful website at http://www.wikihow.com/Clear-Your-Browser's-Cache that has instructions on doing this for Mac or PC (you'll need to scroll down to find PC instructions
You should then close your browser (not merely close the screen, but actually close/shut down the browser), re-launch your browser, and try accessing the content again. You may need to consult your web-browser's help file for instructions on doing this if your browser isn't listed in the above-provided link.