A problem while validating the state of active directory
Setup encountered a problem while validating the state of Active Directory: An Active directory error 0x8007203A occurred when looking for domain controlle rs in domain dom.com: The server is not operational.
Name: "dom.com" The Exchange Server setup operation did not complete.
Visit and enter the Error ID to find more information. Prepare AD will also prepare the root domain so you will not be required to run the /Prepare Domain switch.
However, if you had child domains and you will be installing the Exchange Server on one of those, you will need to do the Prepare Domain switch or while at the root domain, you can do Setup /Prepare Domain "Domain Name" where Domain Name is the name of the domain you need to prepare.
If you are using “Setup.exe,” you should also run this “as the admin.” When it comes to ensuring that your Exchange installation account has the correct permissions within your Active Directory infrastructure, follow the guidance issued in the Tech Net article on preparing Active Directory and domains. Make sure that all of your domain controllers are online and fully functional; there should not be any replication errors.
Additionally, make sure that DNS is functioning correctly within your environment.
I don't know how did you installed schema master because schema master is the forest level role which will be in only one DC server by default your first server.I tried several ways to get a remedy of this issue but no result.I also took necessary measures with my windows firewall.If you have any idea to solve the problem, please help me to get a remedy of this issue. FAILED Active Directory does not exist or cannot be contacted.