I get this error:

[ERROR] Could not load 'plugins/Multiverse-NetherPortals-4.2.1.jar' in folder 'plugins'

org.bukkit.plugin.InvalidPluginException: java.lang.NoClassDefFoundError: com/onarandombox/commandhandler/Command

at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:139) ~[spigot-1.16.5.jar:3002-Spigot-138d451-085fe67]

at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:394) ~[spigot-1.16.5.jar:3002-Spigot-138d451-085fe67]

at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:301) ~[spigot-1.16.5.jar:3002-Spigot-138d451-085fe67]

at org.bukkit.craftbukkit.v1_16_R3.CraftServer.loadPlugins(CraftServer.java:382) ~[spigot-1.16.5.jar:3002-Spigot-138d451-085fe67]

at net.minecraft.server.v1_16_R3.DedicatedServer.init(DedicatedServer.java:185) ~[spigot-1.16.5.jar:3002-Spigot-138d451-085fe67]

at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:809) ~[spigot-1.16.5.jar:3002-Spigot-138d451-085fe67]

at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$0(MinecraftServer.java:164) ~[spigot-1.16.5.jar:3002-Spigot-138d451-085fe67]

at java.lang.Thread.run(Thread.java:748) [?:1.8.0_212]

Caused by: java.lang.NoClassDefFoundError: com/onarandombox/commandhandler/Command

at java.lang.Class.forName0(Native Method) ~[?:1.8.0_212]

at java.lang.Class.forName(Class.java:348) ~[?:1.8.0_212]

at org.bukkit.plugin.java.PluginClassLoader.(PluginClassLoader.java:64) ~[spigot-1.16.5.jar:3002-Spigot-138d451-085fe67]

at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:135) ~[spigot-1.16.5.jar:3002-Spigot-138d451-085fe67]

... 7 more

Caused by: java.lang.ClassNotFoundException: com.onarandombox.commandhandler.Command

at java.net.URLClassLoader.findClass(URLClassLoader.java:382) ~[?:1.8.0_212]

at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:167) ~[spigot-1.16.5.jar:3002-Spigot-138d451-085fe67]

at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:96) ~[spigot-1.16.5.jar:3002-Spigot-138d451-085fe67]

at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[?:1.8.0_212]

at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[?:1.8.0_212]

at java.lang.Class.forName0(Native Method) ~[?:1.8.0_212]

at java.lang.Class.forName(Class.java:348) ~[?:1.8.0_212]

at org.bukkit.plugin.java.PluginClassLoader.(PluginClassLoader.java:64) ~[spigot-1.16.5.jar:3002-Spigot-138d451-085fe67]

at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:135) ~[spigot-1.16.5.jar:3002-Spigot-138d451-085fe67]

... 7 more

You need to update MV Core to the latest version.

I have

It is the latest version.

Then please upload latest.log from the logs folder to something like pastebin.com and give us the link here.

Unfortunately, I can not for privacy reasons. This is not my server and I am making it for a client.

Then you can use mclo.gs, it will automatically remove any IP addresses.

What would you gain from this?

I will be able to tell what the problem is.

I can not provide the full log. I have attached the error I get.

Then I cannot help any further. That error means that MV Core is not up to date, and without the rest of the log I cannot verify that you are indeed using the latest version.

P.S. The latest version is 4.2.2.

I have tried using both.

You tried using both what?

Both versions. The one on Bukkit and 4.2.2

The one on Bukkit is 4.2.2.

Check your plugins folder and make sure there is only one Multiverse-Core jar.

It is Multiverse netherportals, not core.

Multiverse NetherPortals depends on Multiverse-Core. The version of Multiverse-NetherPortals you have installed needs a version of Multiverse-Core of at least 4.2.0.

Sorry if that was not clear.

I have that.

Then again, I cannot help you any further without the full log. Sorry.

Closing the issue due to insufficient information. If you still face issue, then follow the issue template and open a new issue.