My plugins are not working

[fkij]

I installed some plugins on my 1.21 smp, none of them worked. One of them were called RankGrant+ and it said installed on the addons page. But when I do /plugins in my server, it didn't show that the plugin was in the game plus the commands didn't workand for some reason i couldn't take a screenshot of this but when I did /plugins it said exactly this:

Server Plugins (2):

Bukkit Plugins:

- MinehutPlugin, ViaVersion

(the two plugins above were preinstalled and are not of the 3 plugins that didn't work)

[Mwuhh]

I recommend uninstalling the ones you installed through the addons panel Then find and install the plugins you want onto your computer, then from there, manually drag and drop them into the plugins folder -> Then restart your server! 

This is one place to get the plugin you are showing in the picture: https://www.spigotmc.org/resources/rankgrant-give-ranks-through-intuitive-gui-menus-grant.63403/