Edit locally for all files type doesn't work

When I click on “Edit Locally” for a file (example .docx or .txt) othing happens.
Why ?

I am experiencing a perhaps related issue. Running NextCloud 27.0.2 with Desktop Client Version 3.9.3 (macOS).

In Firefox 117, with pop-ups allowed for the site, upon clicking “Edit locally” nothing happens.

It DOES work in Safari: a dialogue appears, “Do you want to allow this page to open “Nextcloud.app”?” — I click Yes, and then the file opens in Word.

However, when visiting the file online via another browser window, it does NOT appear locked—allowing the file to be open in a local editor and in the browser simultaneously. Obviously a problem.