I get to deal with this type of error on a regular basis and, most of the time, end up recommending updating the SQL Server server principal name (SPN) using the setspn utility or simply rebooting the server. I was reading thru the SQL Server CSS blog today and found out another reason for this error message – changed SQL Server service account passwords. While I do not recommend changing the service account passwords during production hours, there may be cases where the account’s password need to be changed as well as the corresponding credentials on the services while waiting for approval for downtime to restart the service. Lesson learned from this blog post is that (1) never change service account passwords during production hours and (2) always restart the SQL Server service immediately after changing the service account password for Kerberos to function properly. No wonder a reboot usually fixes this issue as it also restartes the SQL Server service. I will have to reproduce this to validate