The password manager is sensitive to the domain, so if a website is using more sub domains for load balancing then it is possible that Firefox won't offer to fill the password if it is already stored, but for another domain. Firefox will probably offer to store the password another time when you submit the log in form. Websites may also be using autocomplete=off to prevent Firefox from saving and filling the name and password. In such a case you can remove autocomplete=off with a bookmarklet to make Firefox save names and passwords and other form data. *http://kb.mozillazine.org/User_name_and_password_not_remembered Note that Firefox won't offer to store passwords in a Private Browsing mode window. *https://support.mozilla.org/kb/Private+Browsing ---- *Remember Passwords: https://addons.mozilla.org/firefox/addon/remember-passwords/ *Saved Password Editor: https://addons.mozilla.org/firefox/addon/saved-password-editor/