net.minecraft.network.protocol.game.ClientboundMerchantOffersPacket@61367e1f[
containerId=1
offers=[net.minecraft.world.item.trading.MerchantOffer@feb8a3e, net.minecraft.world.item.trading.MerchantOffer@245cb890, net.minecraft.world.item.trading.MerchantOffer@7993c742, net.minecraft.world.item.trading.MerchantOffer@2b0798e9, net.minecraft.world.item.trading.MerchantOffer@786e4dcd, net.minecraft.world.item.trading.MerchantOffer@3937e268, net.minecraft.world.item.trading.MerchantOffer@5ef98bdb, net.minecraft.world.item.trading.MerchantOffer@49ae803d, net.minecraft.world.item.trading.MerchantOffer@43a4ace0, net.minecraft.world.item.trading.MerchantOffer@4586225e, net.minecraft.world.item.trading.MerchantOffer@5733de66, net.minecraft.world.item.trading.MerchantOffer@6aa113d5, net.minecraft.world.item.trading.MerchantOffer@c0471cd, net.minecraft.world.item.trading.MerchantOffer@78e436c1, net.minecraft.world.item.trading.MerchantOffer@31ed1755, net.minecraft.world.item.trading.MerchantOffer@53b08506, net.minecraft.world.item.trading.MerchantOffer@7c150ca4, net.minecraft.world.item.trading.MerchantOffer@251e7fd9, net.minecraft.world.item.trading.MerchantOffer@7c908390, net.minecraft.world.item.trading.MerchantOffer@2b5fa1b1, net.minecraft.world.item.trading.MerchantOffer@7f7bf852, net.minecraft.world.item.trading.MerchantOffer@29cda0d3, net.minecraft.world.item.trading.MerchantOffer@51b92a79, net.minecraft.world.item.trading.MerchantOffer@73d4bd6, net.minecraft.world.item.trading.MerchantOffer@27249a0b, net.minecraft.world.item.trading.MerchantOffer@63ab7d04, net.minecraft.world.item.trading.MerchantOffer@7b5969ea, net.minecraft.world.item.trading.MerchantOffer@16d7eeac, net.minecraft.world.item.trading.MerchantOffer@15a0dabf, net.minecraft.world.item.trading.MerchantOffer@2d5bd652, net.minecraft.world.item.trading.MerchantOffer@1d7dfc2a, net.minecraft.world.item.trading.MerchantOffer@3476d3a7, net.minecraft.world.item.trading.MerchantOffer@279092b4, net.minecraft.world.item.trading.MerchantOffer@548a3952, net.minecraft.world.item.trading.MerchantOffer@26e41345, net.minecraft.world.item.trading.MerchantOffer@240d17d5, net.minecraft.world.item.trading.MerchantOffer@7ab24d2]
villagerLevel=1
villagerXp=0
showProgress=false
canRestock=false
]

Preliminaries:

• Shopkeepers version: 2.22.3>
• Spigot version: This server is running Paper version 1.21.1-98-master@9b1ee0d (2024-09-24T02:24:07Z) (Implementing API version 1.21.1-R0.1-SNAPSHOT) You are 1 version(s) behind Download the new version at: https://papermc.io/downloads/paper Previous version: 1.21.1-74-971a7a5 (MC: 1.21.1)

• I have checked that my issue/question does not get answered by:
  • The documentation.
  • The FAQ.
  • The Known Issues.
• I have checked all open and closed issues, but none seems to fit my issue/question.

Full server log: https://mclo.gs/mK12bT0

[ItemsAdder] Unhandled exception occurred in onPacketSending(PacketEvent) for ItemsAdder
java.lang.IncompatibleClassChangeError: Found interface org.bukkit.craftbukkit.inventory.CraftMerchant, but class was expected
at ItemsAdder-4.0.2-beta-release-11.jar/ia.nms.v1_21_1.C.a(SourceFile:91) ~[ItemsAdder-4.0.2-beta-release-11.jar:?]

Report this to ItemsAdder: Looks like there was some change in the server, so ItemsAdder needs to be updated to account for that.

Edit: ItemsAdder ticket: PluginBugs/Issues-ItemsAdder#4014