Background: the customer reported that the Windows Server reported an error during automatic update and could not update

Server version: Windows Server 2012 R2 standard

IIS version: 8

WSUS version: 6.3.9600

Error message:

2021-11-29      22:15:10:401      eight hundred and four      cd8      WS      Warning: and at“ http://xxxx.xxxx.xxx.xxx:8530/ClientWebService/client.asmx ”An error occurred while communicating with the endpoint of
2021-11-29      22:15:10:401      eight hundred and four      cd8      WS      Warning: the server has returned the HTTP status code "500 (0x1f4)" and the text "internal server error"
2021-11-29      22:15:10:401      eight hundred and four      cd8      WS      Warning: the server cannot process the request
2021-11-29      22:15:10:401      eight hundred and four      cd8      WS      WARNING: MapToSusHResult mapped Nws error 0x803d000f to 0x8024401f
2021-11-29      22:15:10:401      eight hundred and four      cd8      WS      WARNING: Web service call failed with hr = 8024401f.
2021-11-29      22:15:10:401      eight hundred and four      cd8      WS      WARNING: Current service auth scheme='None'.
2021-11-29      22:15:10:401      eight hundred and four      cd8      WS      WARNING: Proxy List used: '(null)', Bypass List used: '(null)', Last Proxy used: '(null)', Last auth Schemes used: 'None'.
2021-11-29      22:15:10:401      eight hundred and four      cd8      WS      FATAL: OnCallFailure failed with hr=0X8024401F

Troubleshooting steps:

1. Access the URL on the client according to the log   http://xxxx.xxxx.xxx.xxx:8530/ClientWebService/client.asmx

The following occurs:

You can see the specific reason why the client cannot troubleshoot

2. Use the server to directly access the URL   http://xxxx.xxxx.xxx.xxx:8530/ClientWebService/client.asmx

There is an error in which the type cannot be converted

Because I have contacted the code before and thought that some program files of WSUS had problems, I tried to copy files from other WSUS servers for backup and replacement, but it didn’t work

3. Search problem, and finally compare the hosting mode of WSUS service application resource pool in IIS server from “classic” to “integration”

4. When the client accesses the URL again, the following page appears and returns to normal