SuperSocket information: (SpnRegister): error 1355 in Windows application event log

If the SQL Server is unable to register a Service Principal Name (SPN), a SuperSocket information: (SpnRegister): error 1355 message is thrown.

See the Microsoft Support site for information about the Warning SuperSocket Info warning message.

This message is not an error message. This text is only a warning that SQL Server was not able to register a Service Principal Name (SPN), which indicates that the security mechanism used is Microsoft Windows NT Challenge\Response (NTLM) authentication instead of Kerberos. CAUSE The message usually appears because the SQL Server service account is running as a domain user who does not have requisite permissions to register SPNs.