Help!! Re-certify Lotus Notes ID

I have a question. I se Notes Domino Administrator R5 to recertify one of the user ID that expired last month.
I followed the procedure and re-certify it. Even though it said I successfully update the log in the Domino Server, but everytime user tyring to use that ID, Notes won’t let it by saying the ID is still expired as if nothing has changed at all.
Does anyone have any suggestions and idea?
thx in advance.