0x80244081 - One solution

I just debugged an instance of this problem with Wireshark.

In our case the problem is a WatchGuard firewall that "helpfully" converts
an incoming HTTP response to a 403 when it detects what it considers to be
dangerous incoming content, in this case a MIME type of
"multipart/byteranges".

There's a reason the HTTP protocol allows returning content (i.e. text or
HTML) with error responses - SO THE CLIENT CAN TELL THE USER WHAT WENT WRONG!
If the client (in this case MS Update) chooses not to display the content it
just makes things harder for everybody and costs Microsoft lots of support
money.