Cannot add DAG member server in Exchange Server

A DAG is set up in the Exchange Server organization. The next step is to add an Exchange Server member to the DAG. Unfortunately, it fails after going through the operation, and an error appears. In this article, you will learn why you are unable to add a DAG member server.

Unable to add DAG member server

A Database Availability Group (DAG) is configured, and we want to add a new Exchange Server as a DAG member.

Let’s add the Exchange Servers as member servers and click on Save.

The tasks are installing.

An error appears that it can’t add the DAG member server.

A better view of the error is below.

A server-side database availability group administrative 
operation failed. Error The operation failed. CreateCluster 
errors may result from incorrectly configured static 
addresses. Error: Windows Failover Clustering isn't installed 
on 'EX01-2019.exoip.local'.. [Server: EX01-2019.exoip.local]

ERROR

A server-side database availability group administrative 
operation failed. Error The operation failed. CreateCluster 
errors may result from incorrectly configured static 
addresses. Error: Windows Failover Clustering isn't installed 
on 'EX02-2019.exoip.local'.. [Server: EX02-2019.exoip.local]

Why do we get this error, and what is the solution for cannot add DAG member server?

Solution for cannot add member server to DAG

The error about being unable to add a member server to a DAG is because it’s pending an installation. Let’s look more into that.

1. Run PowerShell as administrator

2. Check if the Failover Clustering is installed on the Exchange Server.

The Install State shows the status InstallPending.

PS C:\> Get-WindowsFeature Failover-Clustering | ft -AutoSize

Display Name            Name                 Install State
------------            ----                 -------------
[X] Failover Clustering Failover-Clustering InstallPending

3. Check if the Failover Clustering feature is installed successfully.

Everything looks good. But the Restart shows the value Yes. It means that the Exchange Server needs a restart.

PS C:\> Install-WindowsFeature Failover-Clustering

Success Restart Needed Exit Code      Feature Result
------- -------------- ---------      --------------
True    Yes            NoChangeNeeded {}

4. Reboot the Exchange Server.

Note: The Exchange Server will take some time when restarting because it will install the Failover Clustering feature.

5. Verify that the Failover Clustering feature is successfully installed.

The Install State status appears as Installed.

PS C:\> Get-WindowsFeature Failover-Clustering | ft -AutoSize

Display Name            Name                Install State
------------            ----                -------------
[X] Failover Clustering Failover-Clustering     Installed

6. Return to the Exchange Admin Center and add the Exchange Server as a DAG member.

7. Verify that the Exchange Server appears successfully as a member server in the DAG.

That’s it!

Read more: Recover Exchange DAG member server »

Conclusion

You learned why you cannot add an Exchange Server member to a DAG. The solution to this problem is to check if the Failover Clustering feature is installed or if there is a pending install on the Exchange Server. After a reboot, you can add the Exchange Server as a member to the DAG.

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