Hi @nettech ,
According to the error code 8224, it indicates the main cause is a replication issue with the domain controllers in the environment.
Please refer to the following methods to check whether there are any domain controllers in your environment that are offline or deactivated:
1.Open “Active Directory Sites and Services” , expand all the sites and look at the server names .
2.Check whether there are any old DCs in the list.
3.Delete all the stale Domain Controllers
4.Delete stale Name Servers from DNS properties
5.Reboot all DC's in the site
Finally, try running Prepareschema command on Exchange Server again to see if the error is changed.
In addition , I also search for an official documentation about the error id 8524. It can also be caused by an expired DC or an expired NTDS. You could refer to the following links for troubleshooting:
Active Directory Replication fails with Win32 error 8524 - Windows Server | Microsoft Learn
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