As a first step to isolate the issue, please make sure you are on the latest Safari version (Safari 13). If the issue continues, it is probably because the old Clipper version is still installed and causing conflict on updating to the new version.
If this is the case, please try these steps to uninstall the old Clipper version:
1. Open Safari and select Safari > Preferences from the menu bar.
2. Choose Extensions > Evernote Web Clipper > Uninstall.
3. Quit and reopen Safari.
4. Once Clipper is uninstalled, please go ahead and reinstall it from the App Store.