On starts server. More then 20 error.

[14:50:32] [pool-89-thread-5/ERROR]: [YamipaPlugin] Failed to send FakeEntity packet
java.lang.NullPointerException: Cannot invoke "io.netty.channel.Channel.attr(io.netty.util.AttributeKey)" because "channel" is null
at com.comphenix.protocol.injector.netty.channel.NettyChannelInjector.findInjector(NettyChannelInjector.java:161) ~[ProtocolLib.jar:?]
at com.comphenix.protocol.injector.netty.channel.InjectionFactory.fromPlayer(InjectionFactory.java:103) ~[ProtocolLib.jar:?]
at com.comphenix.protocol.injector.netty.manager.NetworkManagerPlayerInjector.sendServerPacket(NetworkManagerPlayerInjector.java:59) ~[ProtocolLib.jar:?]
at io.josemmo.bukkit.plugin.renderer.FakeEntity.tryToSendPacket(FakeEntity.java:88) ~[YamipaPlugin-1.2.5.jar:?]
at io.josemmo.bukkit.plugin.renderer.FakeItemFrame.render(FakeItemFrame.java:146) ~[YamipaPlugin-1.2.5.jar:?]
at io.josemmo.bukkit.plugin.renderer.FakeImage.nextStep(FakeImage.java:516) ~[YamipaPlugin-1.2.5.jar:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539) ~[?:?]
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305) ~[?:?]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[?:?]
at java.lang.Thread.run(Thread.java:833) ~[?:?]

git-Purpur-1825 (MC: 1.19.2) (Implementing API version 1.19.2-R0.1-SNAPSHOT) (Git: cf6b7c3 on HEAD)
ProtocolLib (5.0.0-SNAPSHOT-b600)
This happens at startup, and periodically while the server is running. It is also possible when a player enters, it should be double-checked.

I cannot reproduce the issue on PurpurMC 1.19.2 (build 1825) with ProtocolLib v5.0.0-SNAPSHOT-b600 and Yamipa v1.2.5.

Are you sure that exception is thrown at server startup when nobody is yet connected? The FakeImage.nextStep() method is only called when a player approaches a placed image.

Yes, I am sure.
latest.log

[20:34:15 INFO]: ------------=[ ServerUtils Plugins ]=-------------
[20:34:15 INFO]: Plugins (114): AdminAnything (2.4.12), AlmostFlatLandsReloaded (1.3.0), AngelChest (9.2.0), AntiAFKPlus (3.11), AsyncWorldEdit (3.9.4), Auto-Tune (0.14.0), BKCommonLib (1.19.2-v2), BetterLogs (2), BlockLocker (1.11), BlueBridgeCore (2.0-s), BlueBridgeWG (2.0-s), BlueMap (3.4), BookNews (6.7), BossLand (0.8), BottledExp (3.1.0.0), Brewery (3.1.1), CMI (9.2.4.3), CMILib (1.2.3.6), Celeste (2.0), ChatLog (1.13.2), ChestSort (13.2.0), Chunky (1.3.38), Citizens (2.0.30-SNAPSHOT (build 2673)), ClickDye (1.0.21), ConsoleSpamFix (1.9.0), CoreProtect (21.2), Corpse (1.0.9-SNAPSHOT), CraftBook (3.10.7;4761-11ee8f6), CreativeManager (1.26), CreepersTrimGrass (1.2), CropChecker (3.1), Dimensions (3.0.10), DiscordSRV (1.26.0), DiscordSRV-Staff-Chat (1.4.4), Disenchant-2 (1.17a), Dynmap-SimpleClans (2.0.3-SNAPSHOT), Dynmap-WorldGuard (1.3-SNAPSHOT), EasyBackup (3.3.7), EasyBackupCore (3.3.6), EnderVaults (1.0.18), EntityDetection (1.2.0 (build #23)), FullMoon (1.2.8), HeadDatabase (4.17.0), HeadSweeper (1.7.2), HeadsPluginAPI (3.1.0), Herobrine (2.4.0), IllegalStack (2.6.1), Insights (6.13.0), Interactions (1.31.1), InvUnload (5.0.0), InvisibleItemFrames (2.7.1), JPremium (CLEARED-Backend-1.16.1), JetpackBasics (1.5.1), Jobs (5.1.0.1), JobsReborn-PatchPlaceBreak (1.2.0), LevelledMobs (3.7.4 b708), LiftReloaded (2.4.0), LightCleaner (1.19-v1), LiquidTanks (2.9.0), LoneLibs (1.0.21), MarketPlace (1.6.0), MobFarmManager (2.0.3.1), Multiverse-Core (4.3.2-SNAPSHOT-b867), Multiverse-Inventories (4.2.2-SNAPSHOT-b499), MultiverseHardcore (1.0.3), NamelessMC (2.1.1), OfflineGrowthPro (1.6.9), PetMaster (1.12.5), Petting (1.3), PhysicsControl (1.1.0), PlaceholderAPI (2.11.2), Plan (5.5 build 1984), ProtocolLib (5.0.0-SNAPSHOT-b600), PublicCrafters (4.13.6), Quests (3.13.2-d709ab4), QuickShop (5.1.0.9), RHLeafDecay (1.19_R1), RadioChannels (1.0), Report (1.1.0), ResourceWorld (1.9.8), SelectionVisualizer (3.2.0.0), Sentinel (2.6.5-SNAPSHOT (build 478)), ServerProtector (1.0), ServerUtils (3.5.3), SignBoard (1.6.13), SimpleClans (2.16.2-51f82ba), SkinsRestorer (14.2.3), Spartan (Phase 484.1), Spectator (1.7), TTA (5.5), TabTPS (1.3.15), TradeMe (6.1.2.0), UltimateStatistics (Phase 111), UltraCustomizer (1.10.0), UltraPermissions (5.3.1), UltraPunishments (2.0.5), UpgradeableHoppers (4.6.0), Vault (1.7.3-CMI), ViaBackwards (4.4.2), ViaVersion (4.4.2), VoidGen (2.2.1), WebConsole (2.4), WikiBook (1.0.6), WorldEdit (7.2.12+6240-87f4ae1), WorldGuard (7.0.8-beta-01+cbb2ba7), WorldGuardExtraFlags (4.2.0), YamipaPlugin (1.2.5), dtlTraders (6.4.16), dwg-oasisdesert (1.1.4), dynmap (3.5-SNAPSHOT-831), floodgate (2.2.0-SNAPSHOT (b73-4f36112)), mcMMO (2.1.217), spark (1.9.9) and wood_cutting (0.0.6-SNAPSHOT)
[20:34:15 INFO]: -------------------------------------------------

Can created NPCs cause this error? Citizens (2.0.30-SNAPSHOT (build 2673))

After a player logs in, the error does not appear immediately.
I could not trace the cause of the error in the course of the server.

start server....
...[20:37:42 ERROR]: [YamipaPlugin] Failed to send FakeEntity packet
java.lang.NullPointerException: Cannot invoke "io.netty.channel.Channel.attr(io.netty.util.AttributeKey)" because "channel" is null
at com.comphenix.protocol.injector.netty.channel.NettyChannelInjector.findInjector(NettyChannelInjector.java:161) ~[ProtocolLib.jar:?]
at com.comphenix.protocol.injector.netty.channel.InjectionFactory.fromPlayer(InjectionFactory.java:103) ~[ProtocolLib.jar:?]
at com.comphenix.protocol.injector.netty.manager.NetworkManagerPlayerInjector.sendServerPacket(NetworkManagerPlayerInjector.java:59) ~[ProtocolLib.jar:?]
at io.josemmo.bukkit.plugin.renderer.FakeEntity.tryToSendPacket(FakeEntity.java:88) ~[YamipaPlugin-1.2.5.jar:?]
at io.josemmo.bukkit.plugin.renderer.FakeItemFrame.render(FakeItemFrame.java:146) ~[YamipaPlugin-1.2.5.jar:?]
at io.josemmo.bukkit.plugin.renderer.FakeImage.nextStep(FakeImage.java:516) ~[YamipaPlugin-1.2.5.jar:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539) ~[?:?]
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305) ~[?:?]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[?:?]
at java.lang.Thread.run(Thread.java:833) ~[?:?]
[20:37:42 WARN]: [dwg-oasisdesert] Plugin is up to date.
[20:49:48 INFO]: ========================
[20:49:48 INFO]: Игроки онлайн 0/100
[20:49:48 INFO]: ========================
[20:49:54 INFO]: UUID of player Tatyana_Snus is 3d3ac104-0005-3211-a663-26b866103980
[20:49:54 INFO]: [CMI] CMIB proxy plugin detected
[20:49:54 WARN]: [CMI] Loaded class me.TechsCode.UltraPermissions.UltraPermissions from UltraPermissions v5.3.1 which is not a depend or softdepend of this plugin.
[20:49:54 INFO]: Tatyana_Snus[/176.196.173.204:38833] logged in with entity id 4421 at ([world]3876.7000000079474, 64.0, -16955.299999992054)
[20:49:55 INFO]: UUID of player MRX_Uchiha is 234a0b88-b0e2-3def-a45b-e1c96c3db3f9
[20:49:56 INFO]: MRX_Uchiha[/212.164.38.52:57501] logged in with entity id 4750 at ([world]4015.758437460221, 56.0, -16879.841577739287)
[20:49:59 INFO]: ========================
[20:49:59 INFO]: Игроки онлайн 2/100
[20:49:59 INFO]: Player: Tatyana_Snus, MRX_Uchiha
[20:49:59 INFO]: ========================

Hello @valenvaio,

What server are you using? Spigot, Paper, etc.
What Minecraft version are you using?
What ProtocolLib version do you have installed?

Does this happen when the server is started or when the first player connects to the server?

Wow, that's quite a long list of plugins... 😬

Can you create a local copy of your server, remove/disable all plugins and start enabling them until you find which one is causing the exception?

It's probably a plugin that has ProtocolLib as a dependency.

_ww.theprogrammersworld.net/Herobrine/download.php
Herobrine v2.4.0
This plugin causes an error. It appears after posting png and gif pictures.

Nice catch! I'll prepare a fix for next version.