If it only fills the username then this could be about legacy saved form data and not about the Password Manager. It is possible that Firefox doesn't recognize this as a login form. You can verify this by right-clicking in the username and password fields where you at least should see manage passwords. You can also check this in the Inspector. *https://firefox-source-docs.mozilla.org/devtools-user/page_inspector/how_to/examine_and_edit_html/ You can click the '+' at the top of the about:logins page to add the login manually yourself. *https://support.mozilla.org/en-US/kb/add-login-firefox-password-manager ---- Suggestions in a login drop-down menu that have a key icon in front are login suggestions that you need to remove in the Password Manager. *https://support.mozilla.org/en-US/kb/password-manager-remember-delete-edit-logins Suggestions in a drop-down menu without a key symbol are autocomplete saved form data. Suggestions without a key icon are part of autocomplete saved form data that you should be able to remove by selecting this item with the cursor Down key and pressing Delete (Mac: Shift+Delete). *https://support.mozilla.org/en-US/kb/control-whether-firefox-automatically-fills-forms