The Autodiscover service could not be located

Question

I am developing small EWS client. For initial testing I wrote simple code:
service = new ExchangeService(ExchangeVersion.Exchange2007_SP1);
service.Credentials = new WebCredentials("[email protected]", "password");
service.TraceEnabled = true;
ServicePointManager.ServerCertificateValidationCallback = CertificateValidationCallBack;
service.AutodiscoverUrl("[email protected]");
I included CertificateValidationCallBack method from
this MSDN page.
I have two Exchange servers. For one exchange server this code worked fine for sending a new email.
However on another server I got following exception:
The Autodiscover service could not be located
at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.InternalGetLegacyUserSettings[TSettings](String emailAddress, List`1 redirectionEmailAddresses, Int32& currentHop)
at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.GetLegacyUserSettings[TSettings](String emailAddress)
at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.InternalGetLegacyUserSettings(String emailAddress, List`1 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 Microsoft.Exchange.WebServices.Data.ExchangeService.AutodiscoverUrl(String emailAddress)
at EwsDctmSyncer.Test.Main(String[] args) in C:\ewswork\csws\EwsTest\EwsExp\Test.cs:line 21
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
When I look at the traces on console, I found this main problem: 
failed: WebException (The underlying connection was closed: Could not
establish trust relationship for the SSL/TLS secure channel.)
However I dont understand what could be wrong with this second instance of Exchange Server. Can anyone pin point what could be wrong. I am puzzled since to my knowledge both the instances are similarly configured.
Added full trace as a reply to this post.

Answer 1

Full Exchange Service Trace:
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:33Z">
Starting SCP lookup for domainName='domain1.com', root path=''
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:33Z">
Searching for SCP entries in LDAP://CN=Configuration,DC=domain1,DC=com
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:33Z">
Scanning for SCP pointers Domain=domain1.com
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:33Z">
No SCP pointers found for 'Domain=domain1.com' in
configPath='CN=Configuration,D
C=domain1,DC=com'
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:33Z">
Scanning for SCP urls for the current computer Site=Default-First-Site-Name
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:33Z">
Adding (prio 1)
'https://exchangeserver.domain1.com/Autodiscover/Autodiscover.xm
l' for the 'Site=Default-First-Site-Name' from
'LDAP://CN=exchangeserver,CN=Auto
discover,CN=Protocols,CN=exchangeserver,CN=Servers,CN=Exchange
Administrative Group (adminGroup),CN=Administrative Groups,CN=domain1,CN=Microsoft
Exchange,
CN=Services,CN=Configuration,DC=domain1,DC=com' to the top of the list (exact ma
tch)
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:33Z">
Trying to call Autodiscover for [email protected] on
https://exchangeserver.domain1.com/Autodiscover/Autodiscover.xml.
</Trace>
<Trace Tag="AutodiscoverRequestHttpHeaders" Tid="9"
Time="2013-12-16 15:40:33Z">
POST /Autodiscover/Autodiscover.xml HTTP/1.1
Content-Type: text/xml; charset=utf-8
Accept: text/xml
User-Agent: ExchangeServicesClient/15.00.0516.014
</Trace>
<Trace Tag="AutodiscoverRequest" Tid="9" Time="2013-12-16 15:40:33Z" Version="15.00.0516.014">
<Autodiscover
xmlns="http://schemas.microsoft.com/exchange/autodiscover/outlook/requestschema/2006">
<Request>
<EMailAddress>[email protected]</EMailAddress>
<AcceptableResponseSchema>http://schemas.microsoft.com/exchange/autodiscov
er/outlook/responseschema/2006a</AcceptableResponseSchema>
</Request>
</Autodiscover>
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:46Z">
failed: WebException (The underlying connection was closed: Could not
establish trust relationship for the SSL/TLS secure channel.)
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:46Z">
Trying to call Autodiscover for [email protected] on
https://domain1.com/aut
odiscover/autodiscover.xml.
</Trace>
<Trace Tag="AutodiscoverRequestHttpHeaders" Tid="9"
Time="2013-12-16 15:40:46Z">
POST /autodiscover/autodiscover.xml HTTP/1.1
Content-Type: text/xml; charset=utf-8
Accept: text/xml
User-Agent: ExchangeServicesClient/15.00.0516.014
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:47Z">
failed: WebException (Unable to connect to the remote server)
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:47Z">
Trying to call Autodiscover for [email protected] on
https://autodiscover.domain1.com/autodiscover/autodiscover.xml.
</Trace>
<Trace Tag="AutodiscoverRequestHttpHeaders" Tid="9"
Time="2013-12-16 15:40:47Z">
POST /autodiscover/autodiscover.xml HTTP/1.1
Content-Type: text/xml; charset=utf-8
Accept: text/xml
User-Agent: ExchangeServicesClient/15.00.0516.014
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:47Z">
failed: WebException (The remote name could not be resolved:
'autodiscover.domain1.com')
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:47Z">
Trying to get Autodiscover redirection URL from
http://autodiscover.domain1.com/
autodiscover/autodiscover.xml.
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:47Z">
Request error: The remote name could not be resolved:
'autodiscover.domain1.com'
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:47Z">
No Autodiscover redirection URL was returned.
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:47Z">
Trying to get Autodiscover host from DNS SRV record for domain1.com.
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:47Z">
DnsQuery returned error error 'DNS name does not exist' error code 0x0000232B.
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:47Z">
No appropriate SRV record was found.
</Trace>
<Trace Tag="AutodiscoverConfiguration" Tid="9" Time="2013-12-16 15:40:47Z">
No matching Autodiscover DNS SRV records were found.
</Trace>