If you receive a message noting that 'reset password is not allowed for migrated users' when trying to reset your password, this may indicate that you have not completed the sign-up process.
Please ask your iThenticate administrator to request a new activation email - make sure to complete all steps in this email before trying to log in and/or reset your password.
iThenticate administrators can resend activation emails by following the steps in the guide Resending an activation email.