I'm getting a few of these warnings on start-up. It's only from the legacy plugins. I have the latest version of spigot 1.15.2 It was only after I updated spigot to the newest version it started to happen. [18:32:24] [Server thread/WARN]: [Vault] Loaded class com.earth2me.essentials.api.Economy from Essentials v2.17.1.27 which is not a depend, softdepend or loadbefore of this plugin.
You're using a slightly outdated version of Essentials, get the new one and it should work. Here's a download location: https://ci.ender.zone/job/EssentialsX/824/
As outdated as anything is, usually you don't have to do anything about warnings. If it's an error, then of course, fix it. However, warnings should be fine. Vault is just saying that it's hooking Essentials Economy
Oh whoops I misread that warning. Yeah it isn't anything to be concerned about, shouldn't even be a warning message.
