one user can't logon its look like a problem of user right's but it dosen't.
the user get the (enter network password) 3 times like the password is
incorect but the password is corect and then eror 401.1
the user member in owa users.
user with the same primisons can logon to the mailbox of
the user with the problem.
even gave the user administrator right but it dosen't help.