Question : Server cert expiry message

HI;
I have around 80 users using Lotus Notes, LD ver 7.0.1. For about two days one of the users gets an error message stating " Server certificate expired" i know how to renew the server certificate but this message is not shown to any other user and i am confused that why only one user receives such message.
Please advice.

Thanks

Answer : Server cert expiry message

I also forget to ask you to make the user access his lotus notes on a different workstation using a different Lotus Notes client . This will be a very good excersise to tell if the user will get the same error or not ????