Edit 22 June 2017: seems to be working after latest update. Thanks, devs.

Won't load the sign-in page. This has been out of action for months now. I installed an older version which worked for a while, but now that's not working either. Very disappointing.

Edit: I followed advice from other users to get it working:
1. go to Preferences > Privacy > History/Cookies > Exceptions and add "https://www.evernote.com/"
2. visit https://www.evernote.com/Login.action?targetUrl=%2FHome.action to create a cookie
3. reinstall the add on.

It works fine for me, love it. Can't wait to get more templates for notes, integration with google sheet, cloud/offline DB query/report!?

In my opinion the latest version of this add-on works great in FF 51/Win10 configuration. You have to check "Remember me for 30 days" ticker AND add set FF to accept and keep cookies from https://evernote.com. Otherwise you will have to log in each time you start FF. With these options set, things works just fine. Clipping, saving PDFs, saving entire Gmail conversation - options I use the most. After successful clipping the note is immediately visible in the web interface and on my phone (after a sync). I give 4* because of the complications with staying logged in.

No problems at all, using Adguard. Therefore I don't know if Adblock is the trouble.

My only niggle is that I'd like the Save button at the bottom of the dropdown, after choosing folder etc - would be more intuitive. And that is such a trivial thing.

I tried the latest web clipper 6.10 with FF 50.1.0 and the latest version of Windows 10. Like many had issues, so I decided to go back to an older version. Here is the version that is working for me.
https://addons.mozilla.org/en-US/firefox/addon/evernote-web-clipper/versions/?page=1#version-6.2.0

I had an error message after installing the extension that the browser could not open the page or whatever but the fix for me was to close the Firefox add-on tab, go to another tab and then click again on the Evernote icon and only then did it work. Maybe that'll be the trick for some others...

Obliged to used Chrome (sorry ;-) in December as Evernote Web Clipper was not working with Firefox. Re-installed today (04 Jan), and it works!

The plugin works again. When my browser closes, all the cookies are cleared, so I lost the login. In this new version the username/password is retrieved from the encrypted firefox password store. Great. Exactly what I wanted. Thanks.

It's a good addon.

If any problem happens in the latest version, you can always go back to older version by downloading from:
https://addons.mozilla.org/en-US/firefox/addon/evernote-web-clipper/versions/

692 삭제하고 620으로 설치하면 됨
https://addons.mozilla.org/en-US/firefox/addon/evernote-web-clipper/versions/
서울휘님 감사~

I use Evernote Clipper and uBlock Origin.
the entry "||evernote.com^$third-party" in Fanboy's Annoyance List block Clipper connect to evernote server.

Apparently the latest firefox update broke a lot of addons, one of them is the evernote web clipper.

uBlock origin (and other ad blockers using adblock rules subscriptions) block work Evernote Web Clipper.

Reason filter "BitBlock List" it contains a rule:
||evernote.com^$third-party

If you disable it, the problem goes away. You can add a filter permitting.
@@||http://evernote.com^

same err with @xRay's, except that I'm using Arch Linux.
After I upgrade Firefox to 50.0, I get this err every time I try to login.