SearxNG search plugin Firefox

Greetings to everyone!
When trying to add the searxng search engine (TrueNAS) to firefox, an error:

Firefox could not download the search plugin from:

This error does not occur when adding searxng from Truecharts.

Haven’t used the application before, but if you’re just trying to change the search engine to something custom have you considered using LibRedirect? You can just point it at your SearXNG instance.

I’ve been using it for years to connect to a SearxNG instance I host in docker (and to redirect various services to their privacy-respecting frontends) and it works perfectly.