I have exactly the same trouble than user 14260550 : i can't authenticate on certain sites (found 2 sites) asking for email and password (web site error : "Forbidden. You don't have permission to access /page_name/ on this server". This bug appears with all my browsers (Firefox, Chrome, Edge) last versions.
I have mentioned this "bug" on community chanel, without any workaround (except than deactivating the extension and clearing cookies when accessing these sites). Everything worked perfectly before with version 7.21 (from memory).
Apart from this big trouble, web clipper works fine for me !

When activated => Aborts a lot of Login pages (with ID and PW request) redirections and displays systematically "Request not allowed."
When deasctivated => everything returns OK...
Issue very hard to find among my numerous Extensions.
Dont forget to clear the cookies of the concerned Login page and of the Parent page by a right-clic on the padlock icon just in front of the adress bar.

Hit and miss, sometimes reinstall needed, just like with Evernote, not ideal, but if you use Evernote, definitely very helpful and with good features, therefore giving 4 stars. [Edit: that's it, no way to get it to work at all, extension keeps reloading infinitely, probably need to fully delete Firefox and set all up from scratch.]

in Firefox funktioniert er seit Wochen NICHT man muß Sites "per Hand" in Notizen einfügen.
Der Support bemüht sich, hat aber auch keinen Plan

doesn't work on firefox since several months. " When I clic on the webclipper button it opens me on new windows sayng "La connexion au Web Clipper a réussi. Vous êtes maintenant connecté. Vous pouvez fermer cette fenêtre.
Bonne capture !"... and nothing else appears + no action is possible

Login to webclipper always fail. See log below pls

2022\2\26 01:09:17 LOG ------ Button clicked -------

2022\2\26 01:10:27 LOG Reloading account in slot 0

2022\2\26 01:10:27 WRN clipper-sso cookie not found!

2022\2\26 01:10:29 LOG Account logged out: o:{"errorCode":5,"parameter":"authenticationToken"}

Version: 7.19.0.324-af67787

I use Evernote-Clipper (and Evernote Premium) now for some years. But this version of the web-clipper is one of the greatest f... I ever installed. Synchronization doesn't work anymore reliable, it stops at 80% or something else.

Leider muss man sich um einen Clip zu machen zuerst umständlich bei evernote anmelden, auch wenn die App geöffnet ist. Sehr, sehr unpraktisch und bei "pocket" viel besser gelöst!

Still broken in Firefox. Can't get more than a star if the extension doesn't work at all.

Nachdem ich die Nutzungsbedingungen gelesen habe, denen ich zustimmen soll, abgebrochen und gelöscht.