WSUS client unable to connect WSUS server

[BoanHed]

I dont know why suddenly all of the WSUS clients are not able to contact WSUS server. I am able to ping the WSUS server from one of the WSUS client machines but if I am typing "http://servername:8530/selfupdate/wuident.cab" then I got page cant be displayed. Is there anyone who can let me know how to troubleshoot this problem? Thanks.

[T.J.]

Did you try to look in the %windir%\WindowsUpdate.log. Also can you tell us whether there is an ISA as on the proxy?

[BoanHed]

Could you please tell me what is ISA? I tried to run the WSUS client diagnostics tool on one of the client machine and I got the following error: WinHttpDownloadFileToMemory<szURLDest, NULL, 0, NULL, &downloadBuffer>
failed with hr=0x80190193

No error description could be found.

When I searched the net for this error code then I found that:
The client does not have sufficient access rights to the requested server object. Cannot execute requested URL in the current application pool IIS returns this error in some transient error cases too such as 403.9 -- Forbidden: Too many clients are trying to connect to the Web server.403.15 -- Forbidden: Client access licenses have exceeded limits on the Web server.

Any ideas?

[vshori]

It seems to be an HTTP '403' error and normally it means that the proxy server on the remote site is blocking access to the website.