Try clearing your cache and cookies. If that doesn't fix it, then whoever is maintaining the site broke something between last night and now.
The message you're getting looks like it is formatted as a
JSON data structure, which means it was probably intended to be interpreted by JavaScript code running in your browser, as opposed to being seen by the end user. There isn't much we can do to figure out what it means, since that would depend on the specifics of the server-side web application and the JavaScript code the server thought was running in your browser.
In other words... "Something Happened".
