If you were added to the system by another author/administrator and haven't been assigned a password yet, you can not obtain a new password via this page.
In this case, you can ask for a username and password from the administrators via the contact page.

Users without an e-mail address who were registered before MiTOS v3, cannot renew passwords via this page.
In this case, users can ask for a new password from the system administrators via the contact page.