Failed to create server implementation. Please report this to the FoliaLib GitHub issues page. Forks of server software may not all be supported. If you are using an unofficial fork, please report this to the fork's developers first.

[nennneko5787]

It was displayed when LunaChat was made compatible with Folia.
Here is the code: https://github.com/Earth2B2TMC/LunaChat/blob/master/src/main/java/com/github/ucchyocean/lc3/LunaChatBukkit.java

[11:52:53 ERROR]: Error occurred while enabling LunaChat v3.0.16 (Is it up to date?)
java.lang.IllegalStateException: Failed to create server implementation. Please report this to the FoliaLib GitHub issues page. Forks of server software may not all be supported. If you are using an unofficial fork, please report this to the fork's developers first.
        at com.tcoded.folialib.FoliaLib.<init>(FoliaLib.java:38) ~[LunaChat.jar:?]
        at com.github.ucchyocean.lc3.LunaChatBukkit.onEnable(LunaChatBukkit.java:77) ~[LunaChat.jar:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:287) ~[folia-api-1.20.4-R0.1-SNAPSHOT.jar:?]
        at io.papermc.paper.plugin.manager.PaperPluginInstanceManager.enablePlugin(PaperPluginInstanceManager.java:188) ~[folia-1.20.4.jar:git-Folia-"25ee657"]
        at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.enablePlugin(PaperPluginManagerImpl.java:104) ~[folia-1.20.4.jar:git-Folia-"25ee657"]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:507) ~[folia-api-1.20.4-R0.1-SNAPSHOT.jar:?]
        at org.bukkit.craftbukkit.v1_20_R3.CraftServer.enablePlugin(CraftServer.java:645) ~[folia-1.20.4.jar:git-Folia-"25ee657"]
        at org.bukkit.craftbukkit.v1_20_R3.CraftServer.enablePlugins(CraftServer.java:556) ~[folia-1.20.4.jar:git-Folia-"25ee657"]
        at net.minecraft.server.MinecraftServer.loadWorld0(MinecraftServer.java:713) ~[folia-1.20.4.jar:git-Folia-"25ee657"]
        at net.minecraft.server.MinecraftServer.loadLevel(MinecraftServer.java:458) ~[folia-1.20.4.jar:git-Folia-"25ee657"]
        at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:309) ~[folia-1.20.4.jar:git-Folia-"25ee657"]
        at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1217) ~[folia-1.20.4.jar:git-Folia-"25ee657"]
        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:346) ~[folia-1.20.4.jar:git-Folia-"25ee657"]
        at java.lang.Thread.run(Thread.java:840) ~[?:?]

[nennneko5787]

Result of executing the about command:

about
[11:59:51 INFO]: Checking version, please wait...
[11:59:52 INFO]: This server is running Folia version git-Folia-"25ee657" (MC: 1.20.4) (Implementing API version 1.20.4-R0.1-SNAPSHOT) (Git: 25ee657)
You are running the latest version

[nennneko5787]

#13 の複製かもしれん
まじでごめんなさい