I’ve had user login problems too. But I got round it by…
(1) login as the admin
(2) Goto “Authors & Users” and then EDIT the user you want
(3) Enter the desired password in the two boxes at the foot of the page
(4) Update User
…and then logout and try logging in as the user with this password.
I’ve had to do this with every user I create – something’s not working right with the initial account setup, but forcing a password reset seems to solve it.
Hope this helps.
