K2 List Method Error

How is your service instance configured for authentication? 

It’s set to service account, although I have tested with Static and Impersonate, which also produce this error only on the list method.

I don’t have it in front of me at the moment but I think there is a setting of some kind like “on same SQL server” - try toggling that value to see if it makes a difference in the error message.

It looks like the issue is related to Kerberos authentication and how credentials are being passed from K2 to SQL Server. The error Login failed for user 'NT AUTHORITY\ANONYMOUS LOGON' suggests that there is a double-hop authentication issue when executing the List method.

A few things to check:

1. Service Instance Authentication: Since you've tested different authentication modes, confirm that the service instance is set to use Service Account and that the account has appropriate permissions on SQL Server.

2. Delegation & Kerberos Configuration: If your K2 environment is using Kerberos, ensure that:

   • The K2 service account has "Trust this user for delegation" enabled in Active Directory.
   • The SQL Server instance has the correct SPNs registered (MSSQLSvc/<servername>:1433).
   • You are using Constrained Delegation if your K2 server and SQL server are on separate machines.

3. K2 Service Account Permissions: Verify that the K2 service account has the necessary database permissions for executing the List method.

4. "On same SQL Server" Option: As @tbyrne777 mentioned, toggling this setting in the service instance might help. If your SQL Server is on a separate machine, K2 may not be correctly handling authentication across machines.

5. Check K2 Logs & SmartObject Tester: Try executing the SmartObject method using SmartObject Tester to see if the issue occurs outside the form as well. Additionally, check K2 host server logs for any additional details.