Outlook requires new authentication

[jose]

Hi,

One user account in our AD domain requires new authentication when starting
Outlook and connecting to Exchange 2003. If he gives his ad domain password
he able to connect his email box.

Have anyone an idea why he is required to give second time his password
although he is successfully logon ad domain with his username and password?
Log into Exchange should be transparent to him like everyone else does.

Thanks,
Jose