Is the wrong version installed? Run npm i --production to ensure the proper composer version is installed.
Otherwise, perhaps the issue has been fixed in a newer version of NodeBB... what commit are you on?
Not quite sure what's happening on my install. Most buttons work but not "reply" and "New Topic".
I should say, don't work anymore, used to work after install.
I did try various browsers.
@andxblink make sure the composer plugin is installed and active?