Thank you for sharing your concern with Aspose support team.
I have noticed that you are using the ExchagneClient class to connect to Exchange Server 2013 which is not the right way as this class is used to connect to servers supporting WebDAV protocol (Exchange Server 2007 & 2010). Exchange Server 2013 doesn’t support the WebDav protocol. Please use the IEWSClient interface (that uses Exchange Web Service) as shown in our documentation article Connecting to Exchange Server for use with Exchange Server 2013.