Retargeter crashes every time i use it

Hey everyone, I am trying to retarget my animations with a custom retargeter (I used a tutorial to make it) and the editor crashes when I click retarget.

This is my crash report:

Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Containers\Array.h] [Line: 752] Array index out of bounds: -1 from an array of size 68

UnrealEditor_AnimationBlueprintLibrary
UnrealEditor_AnimationBlueprintLibrary
UnrealEditor_AnimationBlueprintLibrary
UnrealEditor_AnimationBlueprintLibrary
UnrealEditor_IKRigEditor
UnrealEditor_IKRigEditor
UnrealEditor_IKRigEditor
UnrealEditor_IKRigEditor
UnrealEditor_IKRigEditor
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
user32
user32
InkObj
atlthunk
user32
user32
UnrealEditor_ApplicationCore
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
kernel32
ntdll