Same. The webclipper is acting very buggy. It keeps prompting to log in, and won't clip. It's been useless all day.
Also: After having given up using the clipper, when I've moved on to some other webpage it will suddenly load the clip screen LOL. This makes it extra annoying.
As the OP said, I've also logged out / logged back in to Evernote, closed and reopened the web browser, un-installed and reinstalled the plug in, etc.
It's not helped at all.
I'm hoping this is fixed soon.