ax 2012, KDC_ERR_S_PRINCIPAL_UNKNOWN case-solved

there was a symptom, that around 7-10 minutes, AOS services in one of my AOS server suddenly terminate.
I check the AOS server log, it said that the APP craSH.

but the problem is, this case happen only start from this month only. and it happens maybe 100times until today

I check the event log, I suspect this log indicated the AOS services crash

A Kerberos Error Message was received:
 on logon session 
 Client Time: 
 Server Time: 1:25:37.0000 11/23/2015 Z
 Error Code: 0x7  KDC_ERR_S_PRINCIPAL_UNKNOWN
 Extended Error: 0xc0000035 KLIN(0)
 Client Realm: 
 Client Name: 
 Server Realm: HPG.LOCAL
 Server Name: MSSQLSvc/prod-vm-sql.hpg.local:1433
 Target Name: MSSQLSvc/prod-vm-sql.hpg.local:1433@HPG.LOCAL
 Error Text: 
 File: 9
 Line: f0a
 Error Data is in record data.

after I googling, I found that, when the AOS read the MSSQLSvc on my SQL Database, the Kerberos session has a duplicated security login

so this is the solution:

• when I check the MSSQLSvc/prod-vm-sql.hpg.local:1433 that would be user hpg\app.svc duplicate data on the SPN, so I remove it

  setspn -D MSSQLSvc/prod-vm-sql.hpg.local:1433 hpg\app.svc

• after that, I tried to add (using -S Parameter)

  setspn -S MSSQLSvc/prod-vm-sql.hpg.local:1433 hpg\app.svc

• it shows that this service by this user is already added on the database 

so that was the problem,

after I did the solution, the problem solved.