Clinets are not contacting Wsus Server

Hello,

I have deployed and configured windows update server in my environment and able to cach the updates, the clients have been configured through Group policy and ClientDiag is reporting good, but still I am not seeing any client is showing in un assigned computers. I have noticed the following errros under "WindowsUpdate" log files on client computer running windows XP.

2012-10-01 17:37:48:806 1032 ffc PT WARNING: Cached cookie has expired or new PID is available
2012-10-01 17:37:48:806 1032 ffc PT Initializing simple targeting cookie, clientId = 5580e28f-ace6-490e-8bb4-c90707a1010c, target group = http: //server, DNS name = pc-16.glinksoft.int
2012-10-01 17:37:48:806 1032 ffc PT   Server URL = http:// server/SimpleAuthWebService/SimpleAuth.asmx
2012-10-01 17:37:48:826 1032 ffc PT WARNING: GetAuthorizationCookie failure, error = 0x8024400E, soap client error = 7, soap error code = 400, HTTP status code = 200
2012-10-01 17:37:48:826 1032 ffc PT WARNING: SOAP Fault: 0x000190
2012-10-01 17:37:48:826 1032 ffc PT WARNING:     faultstring:Fault occurred
2012-10-01 17:37:48:826 1032 ffc PT WARNING:     ErrorCode:InternalServerError(5)
2012-10-01 17:37:48:826 1032 ffc PT WARNING:     Message:(null)
2012-10-01 17:37:48:826 1032 ffc PT WARNING:     Method:"http:/ /www.microsoft.com/SoftwareDistribution/Server/SimpleAuthWebService/GetAuthorizationCookie"
2012-10-01 17:37:48:826 1032 ffc PT WARNING:     ID:d04c519e-6890-47ba-a8ef-cefb42dec2dd
2012-10-01 17:37:48:826 1032 ffc PT WARNING: Failed to initialize Simple Targeting Cookie: 0x8024400e
2012-10-01 17:37:48:836 1032 ffc PT WARNING: PopulateAuthCookies failed: 0x8024400e
2012-10-01 17:37:48:836 1032 ffc PT WARNING: RefreshCookie failed: 0x8024400e
2012-10-01 17:37:48:836 1032 ffc PT WARNING: RefreshPTState failed: 0x8024400e
2012-10-01 17:37:48:836 1032 ffc PT WARNING: PTError: 0x8024400e
2012-10-01 17:37:48:836 1032 ffc Report WARNING: Reporter failed to upload events with hr = 8024400e.

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 not running. PASS
        Wuaueng.dll version 7.4.7600.226. . . . . . . . . . . . PASS
                This version is WSUS 2.0

Checking AU Settings
        AU Option is 2 : Notify Prior to Download . . . . . . . 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 not in use

Checking Connection to WSUS/SUS Server
                WUServer = http://server
                WUStatusServer = http://server
        UseWuServer is enabled. . . . . . . . . . . . . . . . . PASS
        Connection to server. . . . . . . . . . . . . . . . . . PASS
        SelfUpdate folder is present. . . . . . . . . . . . . . PASS

Press Enter to Complete

Please help me with this.