HTTP Status 400 Codes (microsoft)
Information about HTTP status codes 400 to 499, their meaning, and any related restrictions.
HTTP code 400 - Client Error
Description
An error situation occurred which seems to be caused by the client. Information about the error should be returned and displayed unless a HEAD request was performed.
Blocked by Windows Parental Controls
Issued by Microsoft when Windows Parental Controls are turned on and a resource is blocked.