Unity SDK

UnityException: FindObjectsOfType can only be called from the main thread.
Constructors and field initializers will be executed from the loading thread when loading a scene.
Don't use this function in the constructor or field initializers, instead move initialization code to the Awake or Start function.
UnityEngine.Object.FindObjectOfType (System.Type type, System.Boolean includeInactive) (at /Users/bokken/buildslave/unity/build/Runtime/Export/Scripting/UnityEngineObject.bindings.cs:415)
UnityEngine.Object.FindObjectOfType[T] () (at /Users/bokken/buildslave/unity/build/Runtime/Export/Scripting/UnityEngineObject.bindings.cs:380)
Modules.DesignPatterns.Singleton.SingletonDontDestroyMono`1[T].get_Instance () (at C:/Data/Projects/Projects-Unity/Libraries/unity_platform_sdks/Library/PackageCache/com.hadh.modules@991c51e7e3/Modules/DesignPatterns/Singleton/SingletonDontDestroyMono.cs:14)
Modules.AdsMediation.Scripts.TopOnAdNetwork.TopOnInterstitialLiteners.onInterstitialAdClose (System.String placementId, AnyThinkAds.Api.ATCallbackInfo callbackInfo) (at C:/Data/Projects/Projects-Unity/Libraries/unity_platform_sdks/Assets/Modules/AdsMediation/Scripts/TopOnAdNetwork/TopOnInterstitialLiteners.cs:50)
AnyThinkAds.Android.ATInterstitialAdClient.onInterstitialAdClose (System.String placementId, System.String callbackJson) (at C:/Data/Projects/Projects-Unity/Libraries/unity_platform_sdks/Assets/AnyThinkAds/Platform/Android/ATInterstitialAdClient.cs:222)
System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at <a1e9f114a6e64f4eacb529fc802ec93d>:0)
Rethrow as TargetInvocationException: AnyThinkAds.Android.ATInterstitialAdClient.onInterstitialAdClose(System.String,System.String)
UnityEngine.AndroidJavaProxy.Invoke (System.String methodName, System.Object[] args) (at /Users/bokken/buildslave/unity/build/Modules/AndroidJNI/AndroidJava.cs:113)
UnityEngine.AndroidJavaProxy.Invoke (System.String methodName, UnityEngine.AndroidJavaObject[] javaArgs) (at /Users/bokken/buildslave/unity/build/Modules/AndroidJNI/AndroidJava.cs:134)
UnityEngine._AndroidJNIHelper.InvokeJavaProxyMethod (UnityEngine.AndroidJavaProxy proxy, System.IntPtr jmethodName, System.IntPtr jargs) (at /Users/bokken/buildslave/unity/build/Modules/AndroidJNI/AndroidJava.cs:980)