FIX THIS ERROR you need Placeholder API. Added Adventure API to te .jar
19:19:32] [Server thread/ERROR]: Error occurred while enabling MXChatManager v1.2.4-SNAPSHOT (Is it up to date?)
java.lang.NoClassDefFoundError: net/kyori/adventure/platform/bukkit/BukkitAudiences
at me.mx.mxchatmanager.MXChatManager.onEnable(MXChatManager.java:68) ~[MXChatManager-1.2.4-SNAPSHOT.jar:?]
at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:264) ~[purpur-api-1.18.2-R0.1-SNAPSHOT.jar:?]
at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:370) ~[purpur-api-1.18.2-R0.1-SNAPSHOT.jar:?]
at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:541) ~[purpur-api-1.18.2-R0.1-SNAPSHOT.jar:?]
at org.bukkit.craftbukkit.v1_18_R2.CraftServer.enablePlugin(CraftServer.java:560) ~[purpur-1.18.2.jar:git-Purpur-1632]
at org.bukkit.craftbukkit.v1_18_R2.CraftServer.enablePlugins(CraftServer.java:474) ~[purpur-1.18.2.jar:git-Purpur-1632]
at net.minecraft.server.MinecraftServer.loadWorld0(MinecraftServer.java:670) ~[purpur-1.18.2.jar:git-Purpur-1632]
at net.minecraft.server.MinecraftServer.loadLevel(MinecraftServer.java:437) ~[purpur-1.18.2.jar:git-Purpur-1632]
at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:352) ~[purpur-1.18.2.jar:git-Purpur-1632]
at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1180) ~[purpur-1.18.2.jar:git-Purpur-1632]
at net.minecraft.server.MinecraftServer.lambda$spin$1(MinecraftServer.java:321) ~[purpur-1.18.2.jar:git-Purpur-1632]
at java.lang.Thread.run(Thread.java:842) ~[?:?]
Caused by: java.lang.ClassNotFoundException: net.kyori.adventure.platform.bukkit.BukkitAudiences
at org.bukkit.plugin.java.PluginClassLoader.loadClass0(PluginClassLoader.java:153) ~[purpur-api-1.18.2-R0.1-SNAPSHOT.jar:?]
at org.bukkit.plugin.java.PluginClassLoader.loadClass(PluginClassLoader.java:105) ~[purpur-api-1.18.2-R0.1-SNAPSHOT.jar:?]
at java.lang.ClassLoader.loadClass(ClassLoader.java:525) ~[?:?]
... 12 more