It looks like you are passing wrong App SID. The SID you sent in a private message does not contain starting 'u'. It starts with '0b3c67ed' but the App SID in your URI starts with 'u0b3c67ed'. Please make sure you are using correct App SID.
Please note in latest API Version of Aspose Cloud APIs, every API has its own storage API methods for Cloud storage operations. So now there is no need to use Aspose.Storage Cloud API in addition to other Aspose.XXXX Cloud API. For example, please check following API methods to create new folder in Cloud storage from Aspose.Words Cloud API and Aspose.PDF Cloud API. You can also get updated SDKs from GitHub repositories.