Check specifially for the server:
setspn -L SERVERNAME
What account is running MSSQLsvc? Does that have an SPN? If it is running a system or network you need to add an SPN for the servename$
setspn -S MSSQLSvc/sql01.domain.com:1433 DOMAIN\servername$
setspn -S MSSQLSvc/sql01.domain.com DOMAIN\servername$
Is it a SQL instance? If so you also need to add a specific SPN for that. Not sure what it is.
That's all I got. Good luck
