Could not obtain information about Windows NT group/user

I have recently started getting this error an a scheduled SQL agent job:

Could not obtain information about Windows NT group/user 'domain\user.name', error code

0x6e.e 

Some web research led me to understand that this error message was the result of SQL trying to validate the job owner credentials against AD using the below SP.

exec xp_logininfo 'domain\user.name'

What I am trying to do is understand how to a> debug this process and\or b> how to resolve the issue without debugging the SP.

Thanks for any and all help!

Shawn