I cant publish mi escene on unity, always send me the same error, even on a diferent version of unity.
NullReferenceException: Object reference not set to an instance of an object
UnityGLTF.GLTFEditorExporter.ExportMaterial (UnityEngine.Material materialObj)
UnityGLTF.GLTFEditorExporter.ExportPrimitive (UnityEngine.GameObject gameObject)
UnityGLTF.GLTFEditorExporter.ExportMesh (System.String name, UnityEngine.GameObject[] primitives)
UnityGLTF.GLTFEditorExporter.ExportNode (UnityEngine.Transform nodeTransform, Int32 nodeCount)
UnityGLTF.GLTFEditorExporter.ExportNode (UnityEngine.Transform nodeTransform, Int32 nodeCount)
UnityGLTF.GLTFEditorExporter.ExportNode (UnityEngine.Transform nodeTransform, Int32 nodeCount)
UnityGLTF.GLTFEditorExporter.ExportScene (System.String name, UnityEngine.Transform[] rootObjTransforms)
UnityGLTF.GLTFEditorExporter.SaveGLTFandBin (System.String path, System.String fileName)
Sketchfab.SketchfabExporter.proceedToExportAndUpload () (at Assets/Sketchfab For Unity/Scripts/SketchfabExporter.cs:299)
Sketchfab.SketchfabExporter.OnGUI () (at Assets/Sketchfab For Unity/Scripts/SketchfabExporter.cs:125)
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:222)
Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation.
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:232)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Reflection/MethodBase.cs:115)
UnityEditor.HostView.Invoke (System.String methodName, System.Object obj) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:295)
UnityEditor.HostView.Invoke (System.String methodName) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:288)
UnityEditor.HostView.InvokeOnGUI (Rect onGUIPosition) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:255)