I run web clipper on 10.15.1 and have checked it, still can't use.
I notice other traditional Chinese user in Taiwan have same problem .
You can check many 1 star review have same problem in Taiwan Mac App Store.
https://apps.apple.com/tw/app/evernote-web-clipper/id1481669779?mt=12
Maybe web clipper have bugs on traditional Chinese system language?