If you made a decision about a particular website storing passwords and you want to clear that out, you should be able to do that here:

orange Firefox button (or Tools menu) > Options > Security

To the right of "Save passwords for sites" there is an Exceptions button. Click that, and see whether you can remove the site there.

If you want to just go ahead and allow it, you also could try this:

Type or paste about:permissions in the URL bar and press Enter. This will load permissions you have set for all sites in various categories. Use the list on the left or the search box there to find the site, then change the Store Passwords permission to Allow.

Any luck?

nope, i checked my Exceptions but there aren't any. They are empty.

The second option doesn't work too. When i put about:permissions in the URL bar and press Enter I don't see that site there.

You can remove all stored data from a specific domain via "Forget About This Site" in the right-click context menu of an history entry (Show All History or History sidebar) or via the about:permissions page.

Using "Forget About This Site" will remove everything like bookmarks, cookies, passwords, cache, history, and exceptions from that domain, so be cautious and if you have a password or other data from that domain that you do not want to lose then make a note of those passwords and bookmarks. You can't recover from that "forget" unless you have a backup of the affected files.

It doesn't have any lasting effect, so if you revisit such a 'forgotten' website then data from that website will be saved once again.

The website may be using autocomplete=off to prevent Firefox from saving and filling the name and password.

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

thank you it helpt :)