Kerberos Unknown Service Errors

An application had an unusually high number of the 0x7 (Unknown Service) error, which indicates that a client requested a service with a service principal name (SPN) that was invalid, unknown, or duplicated. This is a common error if the SPN, which is the unique identifier for services running on servers, has not been correctly set. Troubleshoot these issues with the setspn.exe utility.