How to set up API key

I have tasted the tutorial exactly as described here: Niantic AR Development Kit (ARDK): Authentication and I got the same error message when I try to initialize the session in LowLevelNetworking example scene (when pressing the “Init” button).

Error message:

Exception: Attempting to use networking without setting up your API key or Authentication URL. Set those up through the ARDKAuthRegistrar, or at runtime on ServerConfiguration before using networking!
Niantic.ARDK.Networking._NativeMultipeerNetworking..ctor (Niantic.ARDK.Networking.ServerConfiguration configuration, System.Guid stageIdentifier) (at Assets/ARDK/Networking/_NativeMultipeerNetworking.cs:575)
Niantic.ARDK.Networking.MultipeerNetworkingFactory._Create (Niantic.ARDK.RuntimeEnvironment env, System.Guid stageIdentifier, Niantic.ARDK.Networking.ServerConfiguration configuration) (at Assets/ARDK/Networking/MultipeerNetworkingFactory.cs:218)
Niantic.ARDK.Networking.MultipeerNetworkingFactory.Create (Niantic.ARDK.RuntimeEnvironment env, System.Guid stageIdentifier) (at Assets/ARDK/Networking/MultipeerNetworkingFactory.cs:62)
Niantic.ARDK.Extensions.NetworkSessionManager.Create () (at Assets/ARDK/Extensions/NetworkSessionManager.cs:172)
Niantic.ARDK.Extensions.NetworkSessionManager.InitializeImpl () (at Assets/ARDK/Extensions/NetworkSessionManager.cs:89)
Niantic.ARDK.Extensions.UnityLifecycleDriver.Initialize () (at Assets/ARDK/Extensions/UnityLifecycleDriver.cs:132)
UnityEngine.Events.InvokableCall.Invoke () (at <af218701fe324032b521ddd91f13662b>:0)
UnityEngine.Events.UnityEvent.Invoke () (at <af218701fe324032b521ddd91f13662b>:0)
UnityEngine.UI.Button.Press () (at Library/PackageCache/com.unity.ugui@1.0.0/Runtime/UI/Core/Button.cs:68)
UnityEngine.UI.Button.OnPointerClick (UnityEngine.EventSystems.PointerEventData eventData) (at Library/PackageCache/com.unity.ugui@1.0.0/Runtime/UI/Core/Button.cs:110)
UnityEngine.EventSystems.ExecuteEvents.Execute (UnityEngine.EventSystems.IPointerClickHandler handler, UnityEngine.EventSystems.BaseEventData eventData) (at Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/ExecuteEvents.cs:50)
UnityEngine.EventSystems.ExecuteEvents.Execute[T] (UnityEngine.GameObject target, UnityEngine.EventSystems.BaseEventData eventData, UnityEngine.EventSystems.ExecuteEvents+EventFunction`1[T1] functor) (at Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/ExecuteEvents.cs:262)
UnityEngine.EventSystems.EventSystem:Update() (at Library/PackageCache/com.unity.ugui@1.0.0/Runtime/EventSystem/EventSystem.cs:385)

ARDK v1.1.0
ExamplesPackage 1.1.0
Unity 2020.3.17
Win 10 os