: This official tool from Microsoft Learn can scan your SQL instance and automatically identify missing or misconfigured SPNs.
: Run setspn -X to search for any duplicate SPNs in your domain, which often causes this specific error. : This official tool from Microsoft Learn can
: If the client resolves the server's IP address to a different name than what is stored in Active Directory, the Kerberos ticket request will fail. : Check which account is running the SQL Server service
: Check which account is running the SQL Server service. If it's a domain account, ensure the SPN is registered specifically to that account using the command setspn -L . If it works, the issue is almost certainly
: Try connecting using the server's IP address. If it works, the issue is almost certainly related to SPN or DNS resolution, as IP connections often fall back to NTLM authentication instead of Kerberos. AI responses may include mistakes. Learn more