Check your server log for errors, assuming you are the one hosting it
Text in log file after using Pandora Box and trying to hit spawned mobs
[20:35:24.283] [Main Thread/WARN] [tML]: Silently Caught Exception:
System.IndexOutOfRangeException: Index was outside the bounds of the array.
at HideVanityAccessories.hvaItem.UpdateVanity(Item item, Player player) in HideVanityAccessories\hvaItem.cs:line 10
at Terraria.ModLoader.ItemLoader.UpdateVanity(Item item, Player player) in tModLoader\Terraria\ModLoader\ItemLoader.cs:line 1233
at Hook<System.Void CalamityMod.Graphics.Renderers.CalamityRenderers.DyeableShadersRenderer::CheckVanityDetour(Terraria.On_Player+orig_ApplyEquipVanity_Item,Terraria.Player,Terraria.Item)>(Player , Item )
at SyncProxy<System.Void Terraria.Player:ApplyEquipVanity(Terraria.Item)>(Player , Item )
at Terraria.ModLoader.ModAccessorySlot.ApplyEquipEffects() in tModLoader\Terraria\ModLoader\ModAccessorySlot.cs:line 87
at Terraria.ModLoader.AccessorySlotLoader.CustomUpdateEquips(Int32 index, Player player) in tModLoader\Terraria\ModLoader\AccessorySlotLoader.cs:line 443
at Terraria.ModLoader.Default.ModAccessorySlotPlayer.UpdateEquips() in tModLoader\Terraria\ModLoader\Default\ModAccessorySlotPlayer.cs:line 149
at Terraria.ModLoader.PlayerLoader.UpdateEquips(Player player) in tModLoader\Terraria\ModLoader\PlayerLoader.cs:line 295
at Terraria.Player.UpdateEquips(Int32 i) in tModLoader\Terraria\Player.cs:line 10337
at DMD<System.Void Terraria.Player:Update(System.Int32)>(Player this, Int32 i)
at SyncProxy<System.Void Terraria.Player:Update(System.Int32)>(Player , Int32 )
at DMD<System.Void Terraria.Main

oUpdateInWorld(System.Diagnostics.Stopwatch)>(Main this, Stopwatch sw)
at SyncProxy<System.Void Terraria.Main

oUpdateInWorld(System.Diagnostics.Stopwatch)>(Main , Stopwatch )
at DMD<System.Void Terraria.Main

oUpdate(Microsoft.Xna.Framework.GameTime&)>(Main this, GameTime& gameTime)
at SyncProxy<System.Void Terraria.Main

oUpdate(Microsoft.Xna.Framework.GameTime&)>(Main , GameTime& )
at Terraria.Main.Update(GameTime gameTime)
at Terraria.Main.DedServ_PostModLoad(Boolean& reloadMods)
at Terraria.Main.DedServ()
at Terraria.Program.RunGame()
at Terraria.Program.LaunchGame_(Boolean isServer)
at Terraria.Program.LaunchGame(String[] args, Boolean monoArgs)
at Terraria.MonoLaunch.Main_End(String[] args)
at Terraria.MonoLaunch.<>c__DisplayClass1_0.<Main>b__1()
[20:35:24.338] [Main Thread/WARN] [tML]: Silently Caught Exception:
System.IndexOutOfRangeException: Index was outside the bounds of the array.
at HideVanityAccessories.hvaPlayer.UpdateVisibleAccessory(orig_UpdateVisibleAccessory orig, Player self, Int32 itemSlot, Item item, Boolean modded) in HideVanityAccessories\hvaPlayer.cs:line 43
at Hook<System.Void HideVanityAccessories.hvaPlayer::UpdateVisibleAccessory(Terraria.On_Player+orig_UpdateVisibleAccessory,Terraria.Player,System.Int32,Terraria.Item,System.Boolean)>(Player , Int32 , Item , Boolean )
at SyncProxy<System.Void Terraria.Player:UpdateVisibleAccessory(System.Int32, Terraria.Item, System.Boolean)>(Player , Int32 , Item , Boolean )
at Terraria.ModLoader.Default.ModAccessorySlotPlayer.UpdateVisibleVanityAccessories() in tModLoader\Terraria\ModLoader\Default\ModAccessorySlotPlayer.cs:line 115
at Terraria.ModLoader.PlayerLoader.UpdateVisibleVanityAccessories(Player player) in tModLoader\Terraria\ModLoader\PlayerLoader.cs:line 322
at Terraria.Player.UpdateVisibleAccessories() in tModLoader\Terraria\Player.cs:line 30121
at DMD<System.Void Terraria.Player

layerFrame()>(Player this)
at CalamityMod.ILEditing.ILChanges.CustomGrapplePostFrame(orig_PlayerFrame orig, Player self)
at Hook<System.Void CalamityMod.ILEditing.ILChanges::CustomGrapplePostFrame(Terraria.On_Player+orig_PlayerFrame,Terraria.Player)>(Player )
at SyncProxy<System.Void Terraria.Player

layerFrame()>(Player )
at DMD<System.Void Terraria.Player:Update(System.Int32)>(Player this, Int32 i)
at SyncProxy<System.Void Terraria.Player:Update(System.Int32)>(Player , Int32 )
at DMD<System.Void Terraria.Main

oUpdateInWorld(System.Diagnostics.Stopwatch)>(Main this, Stopwatch sw)
at SyncProxy<System.Void Terraria.Main

oUpdateInWorld(System.Diagnostics.Stopwatch)>(Main , Stopwatch )
at DMD<System.Void Terraria.Main

oUpdate(Microsoft.Xna.Framework.GameTime&)>(Main this, GameTime& gameTime)
at SyncProxy<System.Void Terraria.Main

oUpdate(Microsoft.Xna.Framework.GameTime&)>(Main , GameTime& )
at Terraria.Main.Update(GameTime gameTime)
at Terraria.Main.DedServ_PostModLoad(Boolean& reloadMods)
at Terraria.Main.DedServ()
at Terraria.Program.RunGame()
at Terraria.Program.LaunchGame_(Boolean isServer)
at Terraria.Program.LaunchGame(String[] args, Boolean monoArgs)
at Terraria.MonoLaunch.Main_End(String[] args)
at Terraria.MonoLaunch.<>c__DisplayClass1_0.<Main>b__1()
[20:35:27.964] [Main Thread/WARN] [tML]: Silently Caught Exception:
System.IndexOutOfRangeException: Index was outside the bounds of the array.
at HideVanityAccessories.hvaItem.UpdateVanity(Item item, Player player) in HideVanityAccessories\hvaItem.cs:line 10
at Terraria.ModLoader.ItemLoader.UpdateVanity(Item item, Player player) in tModLoader\Terraria\ModLoader\ItemLoader.cs:line 1233
at Hook<System.Void CalamityMod.Graphics.Renderers.CalamityRenderers.DyeableShadersRenderer::CheckVanityDetour(Terraria.On_Player+orig_ApplyEquipVanity_Item,Terraria.Player,Terraria.Item)>(Player , Item )
at SyncProxy<System.Void Terraria.Player:ApplyEquipVanity(Terraria.Item)>(Player , Item )
at Terraria.ModLoader.Default.ModAccessorySlotPlayer.UpdateEquips() in tModLoader\Terraria\ModLoader\Default\ModAccessorySlotPlayer.cs:line 149
at Terraria.ModLoader.PlayerLoader.UpdateEquips(Player player) in tModLoader\Terraria\ModLoader\PlayerLoader.cs:line 295
at Terraria.Player.UpdateEquips(Int32 i) in tModLoader\Terraria\Player.cs:line 10337
at DMD<System.Void Terraria.Player:Update(System.Int32)>(Player this, Int32 i)
at SyncProxy<System.Void Terraria.Player:Update(System.Int32)>(Player , Int32 )
at DMD<System.Void Terraria.Main

oUpdateInWorld(System.Diagnostics.Stopwatch)>(Main this, Stopwatch sw)
at SyncProxy<System.Void Terraria.Main

oUpdateInWorld(System.Diagnostics.Stopwatch)>(Main , Stopwatch )
at DMD<System.Void Terraria.Main

oUpdate(Microsoft.Xna.Framework.GameTime&)>(Main this, GameTime& gameTime)
at SyncProxy<System.Void Terraria.Main

oUpdate(Microsoft.Xna.Framework.GameTime&)>(Main , GameTime& )
at Terraria.Main.Update(GameTime gameTime)
at Terraria.Main.DedServ_PostModLoad(Boolean& reloadMods)
at Terraria.Main.DedServ()
at Terraria.Program.RunGame()
at Terraria.Program.LaunchGame_(Boolean isServer)
at Terraria.Program.LaunchGame(String[] args, Boolean monoArgs)
at Terraria.MonoLaunch.Main_End(String[] args)
at Terraria.MonoLaunch.<>c__DisplayClass1_0.<Main>b__1()
[20:35:33.701] [Main Thread/WARN] [tML]: Silently Caught Exception:
System.Collections.Generic.KeyNotFoundException: The given key 'CalamityMod/AstralWater' was not present in the dictionary.
at FargowiltasCrossmod.Core.Calamity.Systems.CalDLCFountainDetours.AstralInfectionActive_Detour(Orig_AstralInfectionActive orig, AstralInfectionBiome self, Player player) in FargowiltasCrossmod\Core\Calamity\Systems\CalDLCFountainDetours.cs:line 50
at Hook<System.Boolean FargowiltasCrossmod.Core.Calamity.Systems.CalDLCFountainDetours::AstralInfectionActive_Detour(FargowiltasCrossmod.Core.Calamity.Systems.CalDLCFountainDetours+Orig_AstralInfectionActive,CalamityMod.BiomeManagers.AstralInfectionBiome,Terraria.Player)>(AstralInfectionBiome , Player )
at SyncProxy<System.Boolean CalamityMod.BiomeManagers.AstralInfectionBiome:IsBiomeActive(Terraria.Player)>(AstralInfectionBiome , Player )
at Terraria.ModLoader.BiomeLoader.UpdateBiomes(Player player) in tModLoader\Terraria\ModLoader\BiomeLoader.cs:line 19
at DMD<System.Void Terraria.Player:UpdateBiomes()>(Player this)
at SyncProxy<System.Void Terraria.Player:UpdateBiomes()>(Player )
at ImproveGame.Common.Utils.TileCounter.Simulate(Player player)
at ImproveGame.Content.Tiles.TEAutofisher.FishingCheck()
at ImproveGame.Content.Tiles.TEAutofisher.Update()
at DMD<System.Void Terraria.WorldGen:UpdateWorld_Inner()>()
at SyncProxy<System.Void Terraria.WorldGen:UpdateWorld_Inner()>()
at DMD<System.Void Terraria.WorldGen:UpdateWorld()>()
at SyncProxy<System.Void Terraria.WorldGen:UpdateWorld()>()
at DMD<System.Void Terraria.Main

oUpdateInWorld(System.Diagnostics.Stopwatch)>(Main this, Stopwatch sw)
at SyncProxy<System.Void Terraria.Main

oUpdateInWorld(System.Diagnostics.Stopwatch)>(Main , Stopwatch )
at DMD<System.Void Terraria.Main

oUpdate(Microsoft.Xna.Framework.GameTime&)>(Main this, GameTime& gameTime)
at SyncProxy<System.Void Terraria.Main

oUpdate(Microsoft.Xna.Framework.GameTime&)>(Main , GameTime& )
at Terraria.Main.Update(GameTime gameTime)
at Terraria.Main.DedServ_PostModLoad(Boolean& reloadMods)
at Terraria.Main.DedServ()
at Terraria.Program.RunGame()
at Terraria.Program.LaunchGame_(Boolean isServer)
at Terraria.Program.LaunchGame(String[] args, Boolean monoArgs)
at Terraria.MonoLaunch.Main_End(String[] args)
at Terraria.MonoLaunch.<>c__DisplayClass1_0.<Main>b__1()
[20:35:37.324] [Main Thread/WARN] [tML]: Silently Caught Exception:
System.NullReferenceException: Object reference not set to an instance of an object.
at CalamityMod.Graphics.Renderers.CalamityRenderers.DyeableShadersRenderer.FindDyesDetour(orig_UpdateItemDye orig, Player self, Boolean isNotInVanitySlot, Boolean isSetToHidden, Item armorItem, Item dyeItem) in CalamityMod\Graphics\Renderers\CalamityRenderers\DyeableShadersRenderer.cs:line 67
at Hook<System.Void CalamityMod.Graphics.Renderers.CalamityRenderers.DyeableShadersRenderer::FindDyesDetour(Terraria.On_Player+orig_UpdateItemDye,Terraria.Player,System.Boolean,System.Boolean,Terraria.Item,Terraria.Item)>(Player , Boolean , Boolean , Item , Item )
at CalamityMod.ILEditing.ILChanges.FindCalamityItemDyeShader(orig_UpdateItemDye orig, Player self, Boolean isNotInVanitySlot, Boolean isSetToHidden, Item armorItem, Item dyeItem) in CalamityMod\ILEditing\MechanicILChanges.cs:line 1335
at Hook<System.Void CalamityMod.ILEditing.ILChanges::FindCalamityItemDyeShader(Terraria.On_Player+orig_UpdateItemDye,Terraria.Player,System.Boolean,System.Boolean,Terraria.Item,Terraria.Item)>(Player , Boolean , Boolean , Item , Item )
at InfernumMode.Core.GlobalInstances.Systems.DyeFindingSystem.FindDyes(orig_UpdateItemDye orig, Player self, Boolean isNotInVanitySlot, Boolean isSetToHidden, Item armorItem, Item dyeItem) in InfernumMode\Core\GlobalInstances\Systems\DyeFindingSystem.cs:line 19
at Hook<System.Void InfernumMode.Core.GlobalInstances.Systems.DyeFindingSystem::FindDyes(Terraria.On_Player+orig_UpdateItemDye,Terraria.Player,System.Boolean,System.Boolean,Terraria.Item,Terraria.Item)>(Player , Boolean , Boolean , Item , Item )
at SyncProxy<System.Void Terraria.Player:UpdateItemDye(System.Boolean, System.Boolean, Terraria.Item, Terraria.Item)>(Player , Boolean , Boolean , Item , Item )
at Terraria.Player.UpdateDyes() in tModLoader\Terraria\Player.cs:line 7736
at DMD<System.Void Terraria.Player:Update(System.Int32)>(Player this, Int32 i)
at SyncProxy<System.Void Terraria.Player:Update(System.Int32)>(Player , Int32 )
at DMD<System.Void Terraria.Main

oUpdateInWorld(System.Diagnostics.Stopwatch)>(Main this, Stopwatch sw)
at SyncProxy<System.Void Terraria.Main

oUpdateInWorld(System.Diagnostics.Stopwatch)>(Main , Stopwatch )
at DMD<System.Void Terraria.Main

oUpdate(Microsoft.Xna.Framework.GameTime&)>(Main this, GameTime& gameTime)
at SyncProxy<System.Void Terraria.Main

oUpdate(Microsoft.Xna.Framework.GameTime&)>(Main , GameTime& )
at Terraria.Main.Update(GameTime gameTime)
at Terraria.Main.DedServ_PostModLoad(Boolean& reloadMods)
at Terraria.Main.DedServ()
at Terraria.Program.RunGame()
at Terraria.Program.LaunchGame_(Boolean isServer)
at Terraria.Program.LaunchGame(String[] args, Boolean monoArgs)
at Terraria.MonoLaunch.Main_End(String[] args)
at Terraria.MonoLaunch.<>c__DisplayClass1_0.<Main>b__1()
[20:35:49.108] [Main Thread/WARN] [tML]: Silently Caught Exception:
System.NullReferenceException: Object reference not set to an instance of an object.
at WeaponEnchantments.ModLib.KokoLib.NetManager.NetResetWarReduction(NPC npc) in WeaponEnchantments\ModLib\KokoLib\NetManager.cs:line 73
at KokoLib.KokoLib.HandlePacket(BinaryReader reader, Int32 whoAmI) in KokoLib.cs:line 44
at Terraria.ModLoader.ModNet.HandleModPacket(BinaryReader reader, Int32 whoAmI, Int32 length) in tModLoader\Terraria\ModLoader\ModNet.cs:line 615
at Terraria.MessageBuffer.GetData(Int32 start, Int32 length, Int32& messageType) in tModLoader\Terraria\MessageBuffer.cs:line 3892
at DMD<System.Void Terraria.NetMessage:CheckBytes(System.Int32)>(Int32 bufferIndex)
at SyncProxy<System.Void Terraria.NetMessage:CheckBytes(System.Int32)>(Int32 )
at DMD<System.Void Terraria.Netplay:UpdateServerInMainThread()>()
at SyncProxy<System.Void Terraria.Netplay:UpdateServerInMainThread()>()
at DMD<System.Void Terraria.Main

oUpdate(Microsoft.Xna.Framework.GameTime&)>(Main this, GameTime& gameTime)
at SyncProxy<System.Void Terraria.Main

oUpdate(Microsoft.Xna.Framework.GameTime&)>(Main , GameTime& )
at Terraria.Main.Update(GameTime gameTime)
at Terraria.Main.DedServ_PostModLoad(Boolean& reloadMods)
at Terraria.Main.DedServ()
at Terraria.Program.RunGame()
at Terraria.Program.LaunchGame_(Boolean isServer)
at Terraria.Program.LaunchGame(String[] args, Boolean monoArgs)
at Terraria.MonoLaunch.Main_End(String[] args)
at Terraria.MonoLaunch.<>c__DisplayClass1_0.<Main>b__1()
where

is (.)(Player): (without () )