Why is Windows Update suddenly failing with error 0x80244019?
Solution 1:
Seems like a reboot was all that was needed after adjusting the bypass-list, which must contain <local> so the WinHTTP proxy is bypassed for your local WSUS installation:
netsh winhttp set proxy proxy-server="http=www-proxy:8080" bypass-list="*.domain.example.com;<local>"
Alternatively, if you're already setting the correct proxy in IE (through group policy, for example), you can simply import those settings into WinHTTP:
netsh winhttp import proxy source=ie
To inspect your own current WinHTTP proxy settings, run netsh winhttp show proxy.