Good evening! I would like to ask for your help in enabling the plugin. It suddenly does not work while I was configuring my server and it displayed that there is an internal error. I rebooted the server, and the plugin doesn't work. Here is the part of the log that displays the error:

[15:09:51] [Server thread/WARN]: java.lang.IllegalArgumentException: Name cannot be null
[15:09:51] [Server thread/WARN]: at org.apache.commons.lang.Validate.notNull(Validate.java:192)
[15:09:51] [Server thread/WARN]: at
org.bukkit.craftbukkit.v1_11_R1.CraftServer.getWorld(CraftServer.java:977)
[15:09:51] [Server thread/WARN]: at org.bukkit.Bukkit.getWorld(Bukkit.java:510)
[15:09:51] [Server thread/WARN]: at com.sekwah.advancedportals.portals.Portal.loadPortals(Portal.java:97)
[15:09:51] [Server thread/WARN]: at com.sekwah.advancedportals.portals.Portal.(Portal.java:40)
[15:09:51] [Server thread/WARN]: at com.sekwah.advancedportals.AdvancedPortalsPlugin.onEnable(AdvancedPortalsPlugin.java:45)
[15:09:51] [Server thread/WARN]: at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:271)
[15:09:51] [Server thread/WARN]: at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:329)
[15:09:51] [Server thread/WARN]: at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:404)
[15:09:51] [Server thread/WARN]: at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugin(CraftServer.java:361)
[15:09:51] [Server thread/WARN]: at org.bukkit.craftbukkit.v1_11_R1.CraftServer.enablePlugins(CraftServer.java:323)
[15:09:51] [Server thread/WARN]: at net.minecraft.server.v1_11_R1.MinecraftServer.t(MinecraftServer.java:411)
[15:09:51] [Server thread/WARN]: at net.minecraft.server.v1_11_R1.MinecraftServer.l(MinecraftServer.java:372)
[15:09:51] [Server thread/WARN]: at net.minecraft.server.v1_11_R1.MinecraftServer.a(MinecraftServer.java:327)
[15:09:51] [Server thread/WARN]: at net.minecraft.server.v1_11_R1.DedicatedServer.init(DedicatedServer.java:244)
[15:09:51] [Server thread/WARN]: at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:521)
[15:09:51] [Server thread/WARN]: at java.lang.Thread.run(Unknown Source)
[15:09:51] [Server thread/WARN]: [AdvancedPortals] Something went wrong, please notify sekwah and tell him about this version v:v1_11_R1
[15:09:51] [Server thread/WARN]: [AdvancedPortals] Along with the above stacktrace
[15:09:51] [Server thread/INFO]: �[0;31;1mAdvanced portals are being disabled!�[m

Unfortunately, I'm a newbie at this so I hope you can enlighten me about it so I can fix it myself, the next time it happens. Thanks in advance!

Remove the portal plugin folder. For some reason it is trying to load a portal from a world which isnt loaded. I will add some nullpointers for the next update to stop this crash but for now just get rid of the folder because some portals have invalid data.

Removing the plugin folder seems to fix it. Thanks!

I have made a working fix now for if this error ever comes up again. The portal will just be ignored all together. That way removing worlds will no longer cause issues.