can't login to admin

[dmagic]

after restoring the database ( i drop all tables and restore the database backup)

i can't login , every time show me

"There was a security error when trying to login."

reset password was sent to my email . and i change the password but no success .

in the phpmyadmin

admins - admin_pass i change manuall the password . and i received
You entered the wrong username or password.

help please