Could not obtain information about Windows NT group user
We encountered similar errors in a testing environment on a virtual machine. If the machine name changes due to VM cloning from a template, you can get this error.
If the computer name changed from OLD to NEW.
A job uses this stored procedure:
msdb.dbo.sp_sqlagent_has_server_access @login_name = 'OLD\Administrator'
Which uses this one:
EXECUTE master.dbo.xp_logininfo 'OLD\Administrator'
Which gives this SQL error 15404
select text from sys.messages where message_id = 15404;
Could not obtain information about Windows NT group/user '%ls', error code %#lx.
Which I guess is correct, under the circumstances. We added a script to the VM cloning/deployment process that re-creates the SQL login.
Active Directory is refusing access to your SQL Agent. The Agent should be running under an account that is recognized by STAR domain controller.