2 Domain Controllers on same Internal Network

Question

I have 2 domain controllers DC1 with the IP address 192.168.10.10 and DC2 with the IP address 192.168.10.9 where DNS is installed on both of them

If I make a correction to the DC1 DNS configuration then I can see this correction on the DC2 DNS

The DHCP server delivers an IP address to the clients including dns servers DC1 and DC2

Everything works perfectly

But If I turn off DC1 due to an update then trouble starts

All clients Outlook loses connection to Mailbox until I restart DC1

This doesn't happen if I turn off DC2

I have tryed following commands:
To set the StaticDomainControllers:
Set-ExchangeServer -Identity Mailbox1 -StaticDomainControllers DC2.office.local,DC1.office.local

To set the StaticGlobalCatalogs:
Set-ExchangeServer -Identity Mailbox1 -StaticGlobalCatalogs DC2.office.local,DC1.office.local

To set the StaticConfigDomainController
Set-Exchangeserver Mailbox1 -StaticConfigDomainController DC2.office.local,DC1.office.local

Set-Exchangeserver Mailbox1 -StaticDomainControllers DC2.office.local -StaticGlobalCatalogs DC2.office.local -StaticConfigDomainController DC2.office.local

Set-AdServerSettings -ViewEntireForest $true -PreferredGlobalCatalog dc2.office.local

Set-AdServerSettings -ViewEntireForest $true

Set-ADServerSettings -PreferredServer dc2.office.local

When I check Application log on my Mailbox Event ID 2080 I get following result:
Process Microsoft.Exchange.Directory.TopologyService.exe (PID=5652). Exchange Active Directory Provider has discovered the following servers with the following characteristics:

In-site:
DC2.office.local CDG 1 7 7 1 0 1 1 7 1
DC1.office.local CDG 1 7 7 1 0 1 1 7 1

Out-of-site:

Is it possible to configure On-Premise Exchange 2019 so that it can use both Domain Controllers depending on which one is on ?

A hint would be nice

Best Regards

John B

Answer 1

I solved the problem myself by Manually Configuring DNS Lookups for Exchange Server :-)