Unreal Engine 5.5.3 Multiplayer Menu - Index Error Help!

Hello! I wanted to make a multiplayer menu with Unreal Engine 5.5.3. After making my Blueprints, I pressed the start button, and I got this Index error. Now I am tired. Is my only option to delete my work? Does anyone know a solution?

The Error:

LoginId:ef1c49f04f767b06aa4b80bb741bad12
EpicAccountId:95e6f50a6ffb45aea655e5fa6f008cf5

Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Containers\Array.h] [Line: 783]
Array index out of bounds: 9 into an array of size 0

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kernel32
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