Msg 15404, Level 16, State 10, Procedure xp_logininfo - missing permissions
after checking the error log

xp_readerrorlog 0, 1, "error" , NULL, NULL, NULL, N'desc'


finding no errors related to the above


then checking the error message:

BEGIN TRY  
EXEC xp_logininfo 'gplondon'; 
END TRY  
BEGIN CATCH  
    SELECT ERROR_NUMBER() AS ErrorNumber
          ,ERROR_MESSAGE()
END CATCH; 



  15404
  Could not obtain information about Windows NT group/user
  'gplondon',  error code 0xffff0002.


investigate:
15404 with Active Directory

with a quick select on sys.server_principals 

select * from sys.server_principals
where name = 'gplondon'


I found something obvious: gplondon does not exist in the active directory, because it is a sql login 



from the remarks on the documentation of xp_logininfo


  If account_name is a valid Windows user or group that is not
  associated with a SQL Server login, an empty result set is returned.
  If account_name cannot be identified as a valid Windows user or group,
  an error message is returned.