Your universal link is missing the @instance part at the end, so it tries to redirect to a community called ‘plugins’ on the instance of whoever clicks on it.
This should work for everyone: /c/[email protected]
And if it doesn’t, see the FAQ in the sidebar here; first search for sh.itjust.works/c/plugins on your instance so that it fetches info on the community, then you can click the above link again and it’ll work.
Lemmy Plugins & Userscripts | Personalize and enhance the Lemmy user interface, post and find ways to browse Lemmy more comfortably (sh.itjust.works)
Universal link to the community: /c/plugins...