autodiscover.domain.be

Question

On our exchange server we have a lot of different domains. So we want to set-up what is needed to accomplish that every client can use their autodiscover.owndomain.be to set-up their mailbox in an easy way.
I followed :http://techgenix.com/using-autodiscover-large-numbers-accepted-domains-part1/ => setting up an IIS create a forward to our autodiscover on our mail server: http://webmail.ourdomain.be/autodiscover/autodiscover.xml.
In the binding of the IIS I added (to test) 1 mail domain.

I also added a dns a-record with an unused ip address and then a 1 to 1 natting to the IIS server on our firewall.
The a-record is autodiscover.ourdomain.be 93.93.x.x. TTL 1h

I also played with the settings :

Redirect all requests to exact destination (instead of relative to destination)
Only redirect requests to content in this directory (not subdirectories)

But result stays the same. What I also see is that the automation of the configuration is first pointing to Microsoft 365. But we don't have any licenses for 365. We just used it for Teams. DNS records are not managed by Microsoft. When I cancel that screen I can fill in my password and then it is searching and giving: account cannot be verified.

Can anyone push me in the right direction to work this out? Or give me another link to follow?

Best regards
Kurt

Answer 1

Hi,Kurt.

What I also see is that the automation of the configuration is first pointing to Microsoft 365. But we don't have any licenses for 365. We just used it for Teams.
Are you using Outlook 2016 (version 16.0.6741.2017 or later versions)?
If so, it is an expected behavior.
You can disable this feature by editing the regedit on the client device.
Here are the steps:

1. open regedit.exe and locate HKEY_CURRENT_USER\SOFTWARE\Microsoft\office\16.0\outlook\autodiscover
2. create a new DWORD value named "ExcludeExplicitO365Endpoint" and set its value to 1
   
3. restart Outlook and see if the problem persists

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About the autodiscover issue, please use an account of your test mail domain to run a Test E-mail Autoconfiguration via Outlook.
Check the detailed information about the autodiscover process under the "log" tag.
If autodiscover redirecting is configured properly, the results would be like in the following screenshot:

Here is an article from TechNet for your reference(refer to Scenario 4: Using the Autodiscover service with redirection)
Exchange 2010 Multi-Tenant AutoDiscover Service

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