Regarding "Server URL = http://legacyupdate.net/v6/SimpleAuthWebService/SimpleAuth.asmx" written in WindowsUpdate.log...

[Coffee-geek-officeworker932]

By the way, is "http://legacyupdate.net/v6/SimpleAuthWebService/SimpleAuth.asmx" not implemented or is it just a blank panel?
(When I access that site, it returns a "404 error").

※Update: Sorry, the content I was searching for was too personal, so I trimmed it down lol

[kirb]

The WUv6 endpoints only support POST. When you view it in your browser, you’re making a GET request, which doesn’t match any route on the server, so it will 404.

We currently always return a specific error response when you hit SimpleAuthWebService, so you can see how it responds using curl:

curl -X POST https://legacyupdate.net/v6/SimpleAuthWebService/SimpleAuth.asmx