Notes error: unable to find path to server

Hi Folks,

One of our user is having strange issue. While opening any archived mails from Lotus notes, some mails open with attachment with out any issue but some mails from the same mailbox fails to open giving "Notes Error:Unable to find path to server" (screen shot attached below).

Does any one seen this kind of error before? If yes, please help me in with solution for for it.