That is true. Based on the initial question (and limited info) I assumed that this was a single user issue.
If it’s prompting for all users I doubt it’s one of those two reasons. It could be a DC related issue. I would start with dcdiag\netdiag and exbpa. I encountered this for another client; it ended up being a bad DC (unknown issue but work was done to do it according to user) I ended up excluding DC from dsaccess and went away.