: 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
: The SPN might be missing, duplicated, or registered to the wrong service account (e.g., registered to a domain user when the service is running as LocalSystem ). : Try connecting using the server's IP address
: Recent changes to service accounts or SPNs may not have replicated across all domain controllers yet. Recommended Troubleshooting Steps Learn more : The SPN might be missing,
: Run setspn -X to search for any duplicate SPNs in your domain, which often causes this specific error. The error message typically signals a failure in
The error message typically signals a failure in Kerberos authentication between a client and a SQL Server. It usually means the client cannot verify the identity of the server because of a mismatch or issue with the Service Principal Name (SPN) . Common Root Causes