Re-tested in Firefox, get this message:
The connection was reset
The connection to the server was reset while the page was loading.
The site could be temporarily unavailable or too busy. Try again in a few
moments.
If you are unable to load any pages, check your computer’s network
connection.
If your computer or network is protected by a firewall or proxy, make sure
that Firefox is permitted to access the Web.
I have the same problem. Updated to WordPress 3.6.1 yesterday. After the update when I edit a page or post that contains an image or media item the update fails and shows the following error message:
No Data Received
Unable to load the webpage because the server sent no data.
Reload this webpage.
Press the reload button to resubmit the data needed to load the page.
Error code: ERR_EMPTY_RESPONSE