After facing this issue internally for iPoint and InterAction then at Claymore and ITW I figure a quick check list might help:
1 – Do their machines log directly into the domain?
2 – Do they have active InterAction (or other system) accounts?
3 – Did they change their password recently or have other “account” maintenance done?
4 – Are they relatively new users?
5 – Do they have the website in their local Intranet within IE?
6 – Do they have the security set to auto-login in Intranet zone?