This will get your autodiscover service in Exchange 2007/2010 up and running.
Configure the EWS directory:
# Set-WebServicesVirtualDirectory -Identity “CAS01\EWS (Default Web Site)” -InternalUrl https://CAS01.contoso.local/EWS/Exchange.asmx -ExternalUrl https://mail.contoso.com/EWS/Exchange.asmx
# Set-WebServicesVirtualDirectory -Identity “CAS02\EWS (Default Web Site)” -InternalUrl https://CAS02.contoso.local/EWS/Exchange.asmx -ExternalUrl https://mail.contoso.com/EWS/Exchange.asmx
Configure the OWA directory:
# Set-OwaVirtualDirectory -Identity “CAS01\Owa (Default Web Site)” -InternalUrl https://CAS01.contoso.local/owa -ExternalUrl https://mail.contoso.com/oab
# Set-OwaVirtualDirectory -Identity “CAS02\Owa (Default Web Site)” -InternalUrl https://CAS02.contoso.local/owa -ExternalUrl https://mail.contoso.com/oab
Configure the OAB directory:
# Set-OABVirtualDirectory -Identity “CAS01\OAB (Default Web Site)” -InternalUrl https://CAS01.contoso.local/oab -ExternalUrl https://mail.contoso.com/oab
# Set-OABVirtualDirectory -Identity “CAS02\OAB (Default Web Site)” -InternalUrl https://CAS02.contoso.local/oab -ExternalUrl https://mail.contoso.com/oab
Configure AutodiscoverUri:
# Set-ClientAccessServer -Identity CAS01 -AutoDiscoverServiceInternalUri https://CAS01.contoso.local/autodiscover/autodiscover.xml
# Set-ClientAccessServer -Identity CAS02 -AutoDiscoverServiceInternalUri https://CAS02.contoso.local/autodiscover/autodiscover.xml
Test Outlook autodiscover:
# Test-OutlookWebServices -ClientAccessServer CAS01
My Test lab setting under below
EWS settings checking by using this command
[PS] C:\Windows\system32>Get-WebServicesVirtualDirectory |fl identity,internalurl,externalurl
Identity : CAS01\EWS (Default Web Site)
InternalUrl : https://mail.cas01.com/EWS/Exchange.asmx
ExternalUrl : https://mail.cas01.com/ews/exchange.asmx
Identity : CAS02\EWS (Default Web Site)
InternalUrl : https://mail.cas02.com/EWS/Exchange.asmx
ExternalUrl : https://mail.cas02.com/ews/exchange.asmx
Configuring EWS by using the command
Set-WebServicesVirtualDirectory -Identity “CAS01\EWS (Default Web Site)” -InternalUrl https://mail.testdomain.com/EWS/Exchange.asmx -BasicAuthentication:$true
If you are having two CAS server you have to run this command on both servers
[PS] C:\Windows\system32>Set-WebServicesVirtualDirectory -Identity “CAS02\EWS (Default Web Site)” -InternalUrl https://mail.testdomain.com/EWS/Exchange.asmx -BasicAuthentication:$true
For Autodiscover nad Out Of Office configuration
[PS] C:\Windows\system32>Get-ClientAccessServer |fl -Identity,autodiscoverserviceinternaluri
AutoDiscoverServiceInternalUri : https://mail.testdomain.com/Autodiscover/Autodiscover.xml
AutoDiscoverServiceInternalUri : https://mail.testdomain.com/Autodiscover/Autodiscover.xml
For Setting autodiscover by using shell
[PS] C:\Windows\system32>Set-ClientAccessServer -Identity CAS01 -AutoDiscoverServiceInternalUri https://mail.testdomain.com/Autodiscover/Autodiscover.xml
[PS] C:\Windows\system32>Set-ClientAccessServer -Identity CAS02 -AutoDiscoverServiceInternalUri https://mail.testdomain.com/Autodiscover/Autodiscover.xml
Repository of my experience on Windows Azure Office 365 Intune Teams Exchange Server 
This works – thank you. It is amazing that I read 100 pages of information to finally land here to get it resolved.
Single SBS server – internal url and external need to be the same (create a .com for local resolution in DNS) OR get another certificate for the internal urls.
If the internal and external URL is same you can use same certificate in internal and external URL
I almost never leave comments but just had to say thanks. I was fighting with this problem for most of the day. Now on the the next fire!!
This was very helpful, thank you for putting all this information down in one place!
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Configure the OWA directory:
# Set-OwaVirtualDirectory -Identity “CAS01\Owa (Default Web Site)” -InternalUrl https://CAS01.contoso.local/owa -ExternalUrl https://mail.contoso.com/oab
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I think you need to update ExternalUrl to /owa, not /oab