Connection to Exchange is not available. Autodiscover can not be located

Connection to Exchange is not available. Autodiscover can not be located

I'm using Microsoft Platform Ready Test tool to test a software with
Exchange 2010 + Windows Server 2008 R2. However, I'm stuck on the very
first step when it asks for Exchange 2010 details. I fill in Email, user
name, password, then for the question:
The exchange server I'm connecting to runs on this computer? Yes/No.
no matter I choose yes or no (if no, then I also fill in computer name,
username and password), after I click Verify button, the program got
frozen for some time, then pop a message saying:
Connection to Exchange is not available. Autodiscover can not be located.
In the event viewer, it has one entry:
=================================================== The Autodiscover
service couldn't be located. Server stack trace: at
Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.InternalGetLegacyUserSettings[TSettings](String
emailAddress, List1 redirectionEmailAddresses, Int32& currentHop) at
Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.GetLegacyUserSettings[TSettings](String
emailAddress) at
Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.InternalGetLegacyUserSettings(String
emailAddress, List1 requestedSettings) at
Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.GetUserSettings(String
userSmtpAddress, UserSettingName[] userSettingNames) at
Microsoft.Exchange.WebServices.Data.ExchangeService.GetAutodiscoverUrl(String
emailAddress, ExchangeVersion requestedServerVersion,
AutodiscoverRedirectionUrlValidationCallback
validateRedirectionUrlCallback) at
Microsoft.Exchange.WebServices.Data.ExchangeService.AutodiscoverUrl(String
emailAddress, AutodiscoverRedirectionUrlValidationCallback
validateRedirectionUrlCallback) at
System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr
md, Object[] args, Object server, Int32 methodPtr, Boolean
fExecuteInContext, Object[]& outArgs) at
System.Runtime.Remoting.Messaging.StackBuilderSink.PrivateProcessMessage(RuntimeMethodHandle
md, Object[] args, Object server, Int32 methodPtr, Boolean
fExecuteInContext, Object[]& outArgs) at
System.Runtime.Remoting.Messaging.StackBuilderSink.AsyncProcessMessage(IMessage
msg, IMessageSink replySink)
Exception rethrown at [0]: at
System.Runtime.Remoting.Proxies.RealProxy.EndInvokeHelper(Message reqMsg,
Boolean bProxyCase) at
System.Runtime.Remoting.Proxies.RemotingProxy.Invoke(Object NotUsed,
MessageData& msgData) at
Microsoft.Exchange.WebServices.Data.EwsExtensions.AutodiscoverUrlDelegate.EndInvoke(IAsyncResult
result) at
Microsoft.PlatformReady.MSExchange.Addin.UtilityHelper.<>c_DisplayClassc.b_a(AsyncHandler
handler
===================================================
and on the exchange server (no matter it is another machine or on the same
machine), the iis log has these log:
===============================================
2013-09-05 20:40:12 ::1 GET /autodiscover/autodiscover.xml - 443 - ::1 -
401 0 0 0 2013-09-05 20:40:12 ::1 POST /autodiscover/autodiscover.svc -
443 - ::1 ExchangeServicesClient/14.03.0067.001 401 0 0 15 2013-09-05
20:40:12 ::1 POST /autodiscover/autodiscover.svc - 443 - ::1
ExchangeServicesClient/14.03.0067.001 401 1 3221225581 0 2013-09-05
20:40:33 ::1 POST /Autodiscover/Autodiscover.xml - 443 - ::1
ExchangeServicesClient/14.03.0067.001 401 0 0 0 2013-09-05 20:40:33 ::1
POST /Autodiscover/Autodiscover.xml - 443 - ::1
ExchangeServicesClient/14.03.0067.001 401 1 3221225581 15
===============================================
401 is authentication failed, but I donot know what authentication it needs.
However, if I manually input the autodiscover url in browser, i.e.
https://autodiscover.mydomain.com/autodiscover/autodiscover.xml , it
actually works as it is supposed to be. If i use the remote connectivity
online test to check, it says success, the autodiscover works fine. And if
I use power shell directly: Test-OutlookWebServices , it shows
autodiscover test succeeded. It has some warning the response, but no
error.
Anyone has seen this before? Any ideas what the MPR test tool can not find
the autodiscover?
Any input is appreciated.
Thanks