Seems to be working fine on 1.16, although it looks like it currently has bugs on 1.17. I would recommend reporting this to the developer of the plugin to see if it can be fixed, as there are no new updates currently.
Edit: Also, if you're highly reliant on this plugin working, you may want to keep your server on 1.16 for the time being. There are many missing plugins still on 1.17, and many are buggy. On 1.16 servers you can continue to use all of your favorite plugins, and allow 1.17 players to connect via ViaVersion still (which is automatically installed).