Mac Entourage rejects password

Maybe someone can help me I have a user who just got married, and her email account had to change to reflect her new last name, that was changed no problem but she uses a Mac with Entourage to access her email and when she tries she get a message that tells her that either her username or password is incorrect, but we tried accessing it via the web and it works there, any suggestions.

Thanks in advance.

CG._