App crashes when trying to load .obj file

I am getting a strange error while loading a custom object in sceneview. The application works normally with primitive models. I have an obj file which I try to load in the sceneview and it shows pink screen repeatedly throws error Scenekit index out of capacity. It hangs the whole app and xcode. I get this obj file from server and store it locally in the app in file manager. Please help. I am using Xcode 10 and ios 12 iphone.