z3r0

I’m using Librewolf (a Firefox fork) and have the same issue.

Just check Firefox messaging folder exists in your home

 ls -l ~/.mozilla/native-messaging-hosts

In my case, I needed to create a symlink to make it work with my browser

ln -s ~/.mozilla/native-messaging-hosts ~/.librewolf/native-messaging-hosts

Maybe you could apply a similar workaround. Hope this helps