Unable to Add Exchange Server to DAG – Cluster Join Timeout & ReplServiceNotRunningOnNode Errors

Hi Expertise,

I’m encountering issues while attempting to add a newly deployed mailbox server to an existing DAG in our Exchange Server 2016 on-premises environment. Below is a detailed overview of our environment and the problem scenario.

Environment Overview

• Exchange Version: Exchange Server 2016 (CU version same across all servers)
• Topology: Dual-site (DC & DR)
• Mailbox Servers:
  • DC Site: 3 Mailbox Servers
    • DR Site: 2 Mailbox Servers
    • New Server: A mailbox server recently deployed in DR site (hostname: MBXDR-EXARCH)

Note: Initially, I attempted to deploy a different mailbox server in the DR site but faced multiple issues and could not complete the deployment. That problematic server was decommissioned, and I rebuilt a new server with a different hostname: MBXDR-EXARCH after updating the AD Schema.

·       DAG Type: IP-less DAG

• Networking: Separate NICs for MAPI and Replication traffic
• Cluster Management: Managed automatically by Exchange
• Witness Server: Located on a domain controller (cannot add Exchange Trusted Subsystem to local admins due to DC restrictions)
• CNO: Disabled with proper permissions set
• Active Directory Topology: 4 Domain Controllers total (3 in DC, 1 in DR)
  • Replication Issue Present: One AD server (Not PDC) in the DC site is not replicating to or from other DCs (Vice-Versa). Note: Despite this, I was previously able to add another mailbox server to the DAG from the DR site successfully.

Issue Summary

Initially, the server (MBXDR-EXARCH) was deployed but had multiple issues. I decommissioned it and rebuilt it using a different hostname. When trying to add this server to the DAG, I received the following error:

A server-side database availability group administrative operation failed.
Error: The operation failed. CreateCluster errors may result from incorrectly configured static addresses.
Error: An error occurred while attempting a cluster operation.
Error: Cluster API failed: "AddClusterNode() (MaxPercentage=100) failed with 0x5b4.
Error: This operation returned because the timeout period expired".

After cleanup (removed stale cluster configuration, cleared DAG membership info, verified permissions), I retried and received this new error:

A server-side database availability group administrative operation failed.
Error: The operation failed. CreateCluster errors may result from incorrectly configured static addresses.
Error: An error occurred while attempting a cluster operation.
Error: Node MBXDR-EXARCH is already joined to a cluster.

Event logs from the Primary Active Manager (PAM) server confirm that MBXDR-EXARCH is "already joined to a cluster".

I then attempted to add the server using Exchange Management Shell, but received the following error:

The Microsoft Exchange Replication service does not appear to be running on "PAM Server".
Make sure that the server is operating, and that the services can be queried remotely.

Confirmed that Microsoft Exchange Replication service is running on the PAM and MBXDR-EXARCH. Also tried adding into DAG after rebooting all servers.

Troubleshooting Performed

1. Confirmed all servers have the same Windows updates and patches.
2. Time sync verified via NTP; no drift across servers.
3. Exchange Trusted Subsystem has Full Control on DAG object in AD.
4. IP subnets for DR site correctly defined in AD Sites & Services.
5. Forward and reverse DNS lookups are correct; no stale/duplicate A or PTR records.
6. All Exchange FQDNs resolve across both sites.
7. Only MAPI NICs register in DNS.
8. Witness server is reachable from all DAG members.
9. Witness is hosted on a DC, so Exchange Trusted Subsystem cannot be added to local admins.
10. File share and NTFS permissions verified on Witness.
11. Cluster role is installed and present on MBXDR-EXARCH.
12. TCP port 64327 (Replication) is reachable across servers.

Which components should I verify or reconfigure to help resolve this issue? Please guide me and share the steps I should take to fix the problem. If any additional information is needed, please let me know.

Thanking you.
#ExchangeServer #ExchangeDAG #ExchnageServerManagement