I get this error when working in WordPress, when requesting a page preview from the admin backend on page editing.
I posted a ticket with my host, this is their response.
This looks like a mod_Security error. I cant find anything in the error logs, but I have disabled it for your account - please let us know if that changes anything.
Is there any chance that this plugin is causing this?
I was using chrome browser
Version 22.0.1229.94 m