Read the docs Rated 5 out of 5 stars
It's disappointing that no one bothers to read the extension description fully when setting it up :-/
1- enable password management in firefox (it gets delegated to passifox) tools -> options -> security -> remember passwords for sites
2- follow the directions for naming entry titles or the URL field, use of a domain name is preferred.
3- enjoy, many thousands of people are successfully using this extension on firefox and its sibling extension on chrome (chromeipass)
[n.b obligatory 5-star rating required to post this ;-)]