game crashes when opening custom gui by right clicking my block

i tried so many times to repair this bug but it still here after 3 days. Please help me repair this bug

ERROR
Game Crashed

The game crashed whilst rendering screen
Error: java.lang.ArrayIndexOutOfBoundsException: 7
Ending code: -1

---- Minecraft Crash Report ----
// You should try our sister game, Minceraft!

Time: 14.02.21 20:42
Description: Rendering screen

java.lang.ArrayIndexOutOfBoundsException: 7
at java.util.Arrays$ArrayList.get(Arrays.java:3841) ~[?:1.8.0_51] {}
at net.minecraft.util.NonNullList.get(SourceFile:46) ~[?:?] {re:classloading}
at net.minecraft.tileentity.LockableLootTileEntity.func_70301_a(SourceFile:93) ~[?:?] {re:classloading}
at net.minecraftforge.items.wrapper.InvWrapper.getStackInSlot(InvWrapper.java:68) ~[?:?] {re:classloading}
at net.minecraftforge.items.SlotItemHandler.func_75211_c(SlotItemHandler.java:54) ~[?:?] {re:classloading}
at net.minecraft.client.gui.screen.inventory.ContainerScreen.func_146977_a(ContainerScreen.java:174) ~[?:?] {re:classloading,pl:runtimedistcleaner:A}
at net.minecraft.client.gui.screen.inventory.ContainerScreen.render(ContainerScreen.java:91) ~[?:?] {re:classloading,pl:runtimedistcleaner:A}
at net.mcreator.idk.gui.MechaBuilderGui$GuiWindow.render(MechaBuilderGui.java:322) ~[?:?] {re:classloading,pl:runtimedistcleaner:A}
at net.minecraftforge.client.ForgeHooksClient.drawScreen(ForgeHooksClient.java:368) ~[?:?] {re:classloading}
at net.minecraft.client.renderer.GameRenderer.func_195458_a(GameRenderer.java:480) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.client.Minecraft.func_195542_b(Minecraft.java:924) [?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:553) [?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
at net.minecraft.client.main.Main.main(SourceFile:204) [?:?] {re:classloading}
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_51] {}
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_51] {}
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_51] {}
at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_51] {}
at net.minecraftforge.fml.loading.FMLClientLaunchProvider.lambda$launchService$0(FMLClientLaunchProvider.java:51) [forge-1.15.2-31.2.47.jar:31.2] {}
at net.minecraftforge.fml.loading.FMLClientLaunchProvider$$Lambda$416/1108066952.call(Unknown Source) [forge-1.15.2-31.2.47.jar:31.2] {}
at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-5.1.2.jar:?] {}
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54) [modlauncher-5.1.2.jar:?] {}
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72) [modlauncher-5.1.2.jar:?] {}
at cpw.mods.modlauncher.Launcher.run(Launcher.java:81) [modlauncher-5.1.2.jar:?] {}
at cpw.mods.modlauncher.Launcher.main(Launcher.java:65) [modlauncher-5.1.2.jar:?] {}

A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Thread: Render thread
Stacktrace:
at java.util.Arrays$ArrayList.get(Arrays.java:3841)
at net.minecraft.util.NonNullList.get(SourceFile:46)
at net.minecraft.tileentity.LockableLootTileEntity.func_70301_a(SourceFile:93)
at net.minecraftforge.items.wrapper.InvWrapper.getStackInSlot(InvWrapper.java:68)
at net.minecraftforge.items.SlotItemHandler.func_75211_c(SlotItemHandler.java:54)
at net.minecraft.client.gui.screen.inventory.ContainerScreen.func_146977_a(ContainerScreen.java:174)
at net.minecraft.client.gui.screen.inventory.ContainerScreen.render(ContainerScreen.java:91)
at net.mcreator.idk.gui.MechaBuilderGui$GuiWindow.render(MechaBuilderGui.java:322)
at net.minecraftforge.client.ForgeHooksClient.drawScreen(ForgeHooksClient.java:368)

-- Screen render details --
Details:
Screen name: net.mcreator.idk.gui.MechaBuilderGui.GuiWindow
Mouse location: Scaled: (213, 120). Absolute: (427.000000, 240.000000)
Screen size: Scaled: (427, 240). Absolute: (854, 480). Scale factor of 2.000000

-- Affected level --
Details:
All players: 1 total; [ClientPlayerEntity['tehelon'/197, l='MpServer', x=-55.76, y=64.00, z=154.73]]
Chunk stats: Client Chunk Cache: 441, 289
Level dimension: DimensionType{minecraft:overworld}
Level name: MpServer
Level seed: -8822695988686694610
Level generator: ID 00 - default, ver 1. Features enabled: false
Level generator options: {}
Level spawn location: World: (-48,64,149), Chunk: (at 0,4,5 in -3,9; contains blocks -48,0,144 to -33,255,159), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
Level time: 112882 game time, 112882 day time
Known server brands:
Level was modded: false
Level storage version: 0x00000 - Unknown?
Level weather: Rain time: 0 (now: true), thunder time: 0 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Server brand: forge
Server type: Integrated singleplayer server
Stacktrace:
at net.minecraft.client.world.ClientWorld.func_72914_a(ClientWorld.java:442)
at net.minecraft.client.Minecraft.func_71396_d(Minecraft.java:1763)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:567)
at net.minecraft.client.main.Main.main(SourceFile:204)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at net.minecraftforge.fml.loading.FMLClientLaunchProvider.lambda$launchService$0(FMLClientLaunchProvider.java:51)
at net.minecraftforge.fml.loading.FMLClientLaunchProvider$$Lambda$416/1108066952.call(Unknown Source)
at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37)
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54)
at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72)
at cpw.mods.modlauncher.Launcher.run(Launcher.java:81)
at cpw.mods.modlauncher.Launcher.main(Launcher.java:65)

-- System Details --
Details:
Minecraft Version: 1.15.2
Minecraft Version ID: 1.15.2
Operating System: Windows 10 (amd64) version 10.0
Java Version: 1.8.0_51, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 985462592 bytes (939 MB) / 2147483648 bytes (2048 MB) up to 2147483648 bytes (2048 MB)
CPUs: 6
JVM Flags: 9 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xss1M -Xmx2G -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M
ModLauncher: 5.1.2+70+master.2845bb9
ModLauncher launch target: fmlclient
ModLauncher naming: srg
ModLauncher services:
/mixin-0.8.2.jar mixin PLUGINSERVICE
/eventbus-2.2.1-service.jar eventbus PLUGINSERVICE
/forge-1.15.2-31.2.47.jar object_holder_definalize PLUGINSERVICE
/forge-1.15.2-31.2.47.jar runtime_enum_extender PLUGINSERVICE
/accesstransformers-2.1.3-shadowed.jar accesstransformer PLUGINSERVICE
/forge-1.15.2-31.2.47.jar capability_inject_definalize PLUGINSERVICE
/forge-1.15.2-31.2.47.jar runtimedistcleaner PLUGINSERVICE
/mixin-0.8.2.jar mixin TRANSFORMATIONSERVICE
/forge-1.15.2-31.2.47.jar fml TRANSFORMATIONSERVICE
FML: 31.2
Forge: net.minecraftforge:31.2.47
FML Language Providers:
javafml@31.2
minecraft@1
Mod List:
forge-1.15.2-31.2.47-client.jar Minecraft {minecraft@1.15.2 DONE}
mod.jar idk {idk@1.0.0 DONE}
forge-1.15.2-31.2.47-universal.jar Forge {forge@31.2.47 DONE}
jei-1.15.2-6.0.3.15.jar Just Enough Items {jei@6.0.3.15 DONE}
Launched Version: 1.15.2-forge-31.2.47
Backend library: LWJGL version 3.2.2 build 10
Backend API: GeForce GTX 1050 Ti/PCIe/SSE2 GL version 4.6.0 NVIDIA 456.71, NVIDIA Corporation
GL Caps: Using framebuffer using OpenGL 3.0
Using VBOs: Yes
Is Modded: Definitely; Client brand changed to 'forge'
Type: Client (map_client.txt)
Resource Packs:
Current Language: English (US)
CPU: 6x Intel(R) Core(TM) i5-9400F CPU @ 2.90GHz

Btw i also use JEI mod