Veeam Support case #08047168: Failed to execute SPN registration for service class VeeamAgentWindows

[AZHARI]

Hi,

This is from Veeam Support case # 08047168

I'm currently facing an issue while configuring backups in Failover Cluster mode. The error in the backup job logs indicates a failure during the SPN (Service Principal Name) registration for the service class VeeamAgentWindows.

I've followed the troubleshooting steps provided by Veeam Support (as referenced below), but unfortunately, the issue persists:

https://helpcenter.veeam.com/docs/backu ... ml?ver=120
https://helpcenter.veeam.com/docs/backu ... ml?ver=120
https://learn.microsoft.com/en-us/sql/d ... r16#Manual

Has anyone else encountered a similar issue or found a solution to this? Any help or guidance would be greatly appreciated.

Here's the exact error message from the Svc.VeeamEndpointBackup.log:

From Svc.VeeamEndpointBackup.log, I see the below:
[14.04.2026 12:03:33] <04> Info Connecting to VBR in managed mode
[14.04.2026 12:03:33] <04> Info SPN registration: registering for computer account name 'HOSTNAME'
[14.04.2026 12:03:33] <04> Info Domain name: XXX.COM
[14.04.2026 12:03:33] <04> Info Use domain controller: XXXXXXX.XXX.COM
[14.04.2026 12:03:33] <04> Info Execute SPN registration for user 'CN=SA-KGP-VB-PRD-BKP,CN=Managed Service Accounts & Groups,DC=XXX,DC=COM'
[14.04.2026 12:03:33] <04> Error Failed to execute SPN registration for service class VeeamAgentWindows
[14.04.2026 12:03:33] <04> Error Failed to registry. Result: '8235' Error: 'ERROR_DS_REFERRAL' (System.Exception)
[14.04.2026 12:03:33] <04> Error at Veeam.Backup.Common.SKerberosHelper.CSpnRegister.RegistrySpnByUserName(IntPtr hDS)
[14.04.2026 12:03:33] <04> Error at Veeam.Backup.Common.SKerberosHelper.CSpnRegister.TryExecute(String computerAccountName, String& exception)
[14.04.2026 12:03:33] <04> Error Failed to registry SPN VeeamAgentWindows

[david.domask]

Hi AZHARI, welcome to the forums.

Thank you for sharing the case number and sorry to hear about the challenges.

Please continue with Veeam Support; at first blush the issue doesn't immediately match with any known issues, so likely further investigation will be required.

If you have concerns about the handling / progress of the case, use the Talk to a Manager button in the Case Portal to reach out to Support Management; they will review your concerns and the case, and allocate additional resources as necessary.