firebase-ios-sdk: Firebase Fabric Crashlytics not sending data to server

I think I’ve done the integration correctly. Everything looks ok. However data doesn’t get sent (or received). I think the problem is in this message that I get in the debug console (Xcode).

[Fabric] failed to download settings Error Domain=FABNetworkError Code=-5 "(null)" UserInfo={status_code=403, type=2, request_id=2ee223feb3c7053579a2136db09a5749, content_type=application/json; charset=utf-8}

please give some solution