Exchange 2019 forest/child domain setup.

asked 2022-06-16T20:03:15.383+00:00
Miles M 1 Reputation point


We're setting up Exchange 2019 (brand new instance, no older versions exist) in a forest/child domain environment. I understand the first step aside from installing prerequisites is to extend the Active Directory schema with the /prepareschema and /preparead commands. /preparealldomains threw errors which I assume were intended as the /preparead step takes care of that. We have our first Exchange server setup and attempted doing this on the child domain level with no luck (kept saying my account wasn't an Enterprise level admin and that the functional level of our DC was not Windows Server 2012 or above, which it is). My account is part of both the Schema and Enterprise admins groups. I since moved the server to the forest level and both commands appeared to go through and I installed the main Exchange setup. Now the Administrative Center link throws a giant "Server Error in '/ecp' Application" error and verbiage suggesting it cannot talk to the child Active Directory server. So it looks like the whole thing is botched. I can't paste exact errors as it's an air-gapped network.

Question is in a forest/child setup where is the Exchange server supposed to exist? There's currently only one child domain that has all the AD users. I thought the schema prep was supposed to be done on both forest and child levels. Do the commands not take care of both? Is there best practices or specific documentation on setting Exchange up in this type of environment?


Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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  1. answered 2022-06-17T06:04:55.46+00:00
    Aaron Xue-MSFT 2,576 Reputation points Microsoft Employee

    Hi @Miles M ,

    It seems you have already installed the Exchange server successfully.

    If you are looking for how to install Exchange server in child domain, here’s a similar thread for you reference. Although it is Exchange server 2013, but it’s same to Exchange server 2019.
    How to Install Exchange Server in Child Domain Server (

    Is there any other exchange server in your environment?

    According to the error message” Server Error in '/ecp' Application”, The issue may occur with the Oauth certificate is missing from the Exchange server.

    I found it’s documented in below link. Please reference it and be free to feed back.
    You can't access OWA or ECP after you install Exchange Server 2016 CU6 (

    If the response is helpful, please click "Accept Answer" and upvote it.

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