Hi When my users want to access their e-mail in Outlook Web Access, receive this message: The user name or password that you entered is not valid. Try entering it again. However they use right user name and password and type it correct but they receive that message !

I check my user properties in AD and noticed that those user have Log on to restriction can not log in to their mail box. So i let them log on to my exchange server by its computer name and so problem solved.