Receive Server Error while browsing the Exchange EWS or Autodiscover sites


Recently i received the following error while try to browse the following /autodiscover/Autodiscover.xml">https://<servername>/autodiscover/Autodiscover.xml  or /ews/exchange.asmx">https://<servername>/ews/exchange.asmx:


Could not load file or assembly 'Microsoft.Exchange.Diagnostics, Version=8.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.Exchange.Diagnostics, Version=8.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Assembly Load Trace: The following information can be helpful to determine why the assembly 'Microsoft.Exchange.Diagnostics, Version=8.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' could not be loaded.

WRN: Assembly binding logging is turned OFF.
To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1.
Note: There is some performance penalty associated with assembly bind failure logging.
To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog].

Stack Trace:

[FileNotFoundException: Could not load file or assembly 'Microsoft.Exchange.Diagnostics, Version=8.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.]
Microsoft.Exchange.Services.AuthorizationModule.Init(HttpApplication context) +0
System.Web.HttpApplication.InitModulesCommon() +135
System.Web.HttpApplication.InitInternal(HttpContext context, HttpApplicationState state, MethodInfo[] handlers) +2601588
System.Web.HttpApplicationFactory.GetNormalApplicationInstance(HttpContext context) +347
System.Web.HttpApplicationFactory.GetApplicationInstance(HttpContext context) +139
System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr) +196

--------------------------------------------------------------------------------
Version Information: Microsoft .NET Framework Version:2.0.50727.1434; ASP.NET Version:2.0.50727.1434

During the analysis, i noticed that the issue had happened as it could not load the assembly Microsoft.Exchange.Diagnostics due to incorrect entry in the application web.config file. I followed the below steps to over come the issue specified in the KB.

If the problem is occurring with /autodiscover/autodiscover.xml">https://<servername>/autodiscover/autodiscover.xml

Take a backup of web.config in "C:\Program Files\Microsoft\Exchange Server\ClientAccess\Autodiscover".
- Open web.config from C:\Program Files\Microsoft\Exchange Server\ClientAccess\Autodiscover in notepad.
- Replace all "file:///%ExchangeInstallDir%" with "file:///C:\Program Files\Microsoft\Exchange Server\" where C is the drive where Exchange is installed.
- Save the file.
- Open an Administrator command prompt and run IISreset /noforce
- Test browsing /autodiscover/autodiscover.xml">https://<servername>/autodiscover/autodiscover.xml

If the problem is occurring with /ews/exchange.asmx">https://<servername>/ews/exchange.asmx 

Take a backup of web.config in "C:\Program Files\Microsoft\Exchange Server\ClientAccess\exchweb\ews".
- Open web.config from C:\Program Files\Microsoft\Exchange Server\ClientAccess\exchweb\ews in notepad.
- Replace all "file:///%ExchangeInstallDir%" with "file:///C:\Program Files\Microsoft\Exchange Server\" where C is the drive where Exchange is installed.
- Save the file.
- Open an Administrator command prompt and run IISreset /noforce
- Test browsing /ews/exchange.asmx">https://<servername>/ews/exchange.asmx

Hope this helps.

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