Outlook client ignores AutoDiscover Site Affinity

Outlook 2007 or newer clients always connect to the Exchange 2007/2010/2013 Client Access server that was recently installed to get Autodiscover  information instead of connecting to the closest Active Directory site with Exchange 2007/2010/2013 Client Access server installed.

This happens despite the “AutoDiscoverSiteScope” appears to be properly configured:

Get-ClientAccessServer  | ft name, AutoDiscoverSiteScope
Name            AutoDiscoverSiteScope
—-            ———————
SERV-01       {SiteA, SiteB}
SERV-02       {SiteC, SiteD}

When configuring the AutoDiscoverSiteScope option with Set-ClientAccessServer the following syntax is used:

Set-ClientAccessServer -Identity SRV-01 -AutodiscoverSiteScope “SiteA, SiteB”

However the underlying Active Directory object (e.g. CN=SRV-01,CN=Autodiscover,CN=Protocols,CN=SRV-01,CN=Servers,CN=Exchange Administrative Group (FYDIBOHF23SPDLT), CN=Administrative Groups,CN=First Organization, CN=Microsoft Exchange, CN=Services,CN=Configuration, DC=contoso,DC=com) indicates the syntax of command is incorrect because “SiteA, SiteB”  is considered as the site name when examined with ADSIEdit:

Site Affinity is misconfigured
Site Affinity is misconfigured

This happens because the Set-ClientAccessServer cmdlet does not validate whether the entered site name corresponds to a real Active Directory site.

To configure AutodiscoverSiteScope option in case of multiple sites use the below syntax:

Set-ClientAccessServer -Identity SRV-01 -AutodiscoverSiteScope “SiteA”,” SiteB”

Use ADSIEdit to validate the Active Directory object has the sites listed properly:

Site Affinity is configured correctly
Site Affinity is configured correctly