Outlook 2007 Certificate Error?

Published: 19th September 2008
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When importing a new certificate into Exchange 2007, you might encounter a

certificate error in Outlook 2007. I have included a screenshot of the error I

encountered today:

When you choose the View Certificate button, it brings up another window that

shows you what certificate is in error. In this case, the certificate name is "mail.shudnow.net."

So the million dollar question? Why the error?

Well, when we install a new certificate, there are a few tasks we want to do.

Obviously, we install the certificate for a purpose. This purpose is till allow

us to use Exchange services securely. So how do we enable Exchange to use these

services? If you are planning to do a very simple configuration and do not care

about external Autodiscover access, you do not need to use a Unified

Communication Certificate. You can read more about these certificates in one of

my other articles here.

So let's say we have a simple regular common certificate. A certificate with a

Common Name (CN) of mail.shudnow.net We install this certificate onto our

Exchange box with its' private key. In our case we were migrating so we did not

have to request a certificate via IIS. We just exported it with its' private key

and imported onto the new box. We then assigned this certificate to IIS. Now I

went to the Exchange Management Shell and enabled Exchange services to use this

certificate. In order to do this, you must run the following commands:


Thumbprint Services Subject

---- --- ---

BCF9F2C3D245E2588AB5895C37D8D914503D162E9 SIP.W CN=mail.shudnow.net.com

What I did was go ahead and enable all new services to use every available

service by using the following command:

Enable-exchangecertificate -services IMAP, POP, UM, IIS, SMTP -Thumbprint


The next step would be to ensure the AutodiscoverInternalURI is pointed to the

CAS that will be your primary CAS for Autodiscover servicing.

Get-ClientAccessServer -Identity CASServer | FL

AutoDiscoverServiceInternalUri : https://casnetbiosname/Autodiscover/Autodiscover.xml

See the issue here? We are not using a UC certificate that contains the names,

"casnetbiosname, casnetbiosname.shudnow.net, mail.shudnow.net, and

autodiscover.shudnow.net" Since the Autodiscover directory in IIS will be

requring SSL encryption, the url specified in the AutoDiscoverServiceInternalURI

must match what is specified in your certificate. You must also ensure there is

a DNS record that allows mail.shudnow.net to resolve to your CAS. We should

re-configure the AutoDiscoverServiceInternalURI by using the following command:

Set-ClientAccessServer -Identity CASServer -AutoDiscoverServiceInternalUri


We now need to go configure all the InternalURLs for each web distributed

service. If you are going to be utilizing the Autodiscover service from the

outside or for non-domain joined clients, you may want to configure an -ExternalURL

in addition to your -InternalURL.

Here is the reason why we were receiving the certificate errors. Your

InternalURLs most likely are not using mail.shudnow.net. Your InternalURLs are

most likely pointed to something such as https://casnetbiosname/ServiceURL which

will fail since this is not the CN of your simple certificate.

You can run the following commands to fix your internalURLs so your Outlook 2007

client can successfully take advantage of your web distribution services.

Set-WebServicesVirtualDirectory -Identity "CASServerEWS (Default Web Site)" -InternalURL

https://mail.shudnow.net/EWS/Exchange.asmx -BasicAuthentication:$true

Set-OABVirtualDirectory -Identity "CASServerOAB (Default Web Site)" -InternalURL


Note: You must ensure that you enable SSL on the OAB directory in IIS which is

not on by default. The same goes for Basic Authentication on the OAB directory.

The above command will only enable SSL, but will not ensure 128-bit SSL is


Enable-OutlookAnywhere -Server CASServer -ExternalHostname "mail.shudnow.net" -ExternalAuthenticationMethod


Note: The above Enable-OutlookAnywhere command works on RTM. For SP1, substitute

-ExternalAuthenticationMethod with -ClientAuthenticationMethod.

Set-ActiveSyncVirtualDirectory -Identity "CASServerMicrosoft-Server-ActiveSync

(Default Web Site)" -ExternalURL https://mail.shudnow.net/Microsoft-Server-Activesync

Set-UMVirtualDirectory -Identity "CASServerUnifiedMessaging (Default Web Site)"

-InternalURL https://mail.shudnow.net/UnifiedMessaging/Service.asmx -BasicAuthentication:$true

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