A "406 Not Acceptable" error is shown when a website, script or application has triggered our security filters (mod_security) used to automatically block attacks on vunerable scripts.
In the vast majority of cases clients should never see this because our rules are designed to be unobtrusive (only blocking clear attempts to comprimise security with the minimum of 'false positives'). If the error is seen at any point please open a support ticket for us to look into it for you.
