WSUS Connection to server error

> Hi,
> I have installed WSUS Server on a windows 2003 server and it is getting
> update online without any error through proxy.
> When I launch the WSUS Diagnostic tool, an error occurs. Here is the log:
> <
> WSUS Client Diagnostics Tool
>
> Checking Machine State
> Checking for admin rights to run tool . . . . . . . . . . . . . . PASS
> Automatic Updates Service is running. . . . . . . . . . . . . PASS
> Background Intelligent Transfer Service is running. . . PASS
> Wuaueng.dll version 5.4.3790.2180 . . . . . . . . . . . . . . PASS
> This version is SUS 1.0
>
> Checking AU Settings
> AU Option is 4: Scheduled Install . . . . . . . . . . . . . . . . PASS
> Option is from Policy settings
>
> Checking Proxy Configuration
> Checking for winhttp local machine Proxy settings . . . PASS
> Winhttp local machine access type
> <Direct Connection>
> Winhttp local machine Proxy. . . . . . . . . . . . . . . . .
> NONE
> Winhttp local machine ProxyBypass. . . . . . . . . . . NONE
> Checking User IE Proxy settings . . . . . . . . . . . . . . . . . PASS
> User IE Proxy. . . . . . . . . . . . . . . . . . . . . . . .
> . . . . . NONE
> User IE ProxyByPass. . . . . . . . . . . . . . . . . . . . .
> . . NONE
> User IE AutoConfig URL Proxy . . . . . . . . . . . . . . .
> NONE
> User IE AutoDetect
> AutoDetect in use
>
> Checking Connection to WSUS/SUS Server
> WUServer = http://MyServer:8530
> WUStatusServer = http://MyServer:8530
> UseWuServer is enabled. . . . . . . . . . . . . . . . . . . . . . .
> . PASS
> Connection to server. . . . . . . . . . . . . . . . . . . . . . . .
> . . . PASS
>
> WinHttpDownloadFileToMemory(szURLDest, NULL, 0, NULL, NULL, NULL,
> &downloadBuffer) failed with hr=0x80190191
>
> No Error description could be found

> >

> Could anybody tell me how to fix this problem?