Mono C# .NET 4.6 async and await problem

I am attempting to get a Visual Studio example project in a Unity 2017 (with .NET 4.6 enabled) project. The example project is here: [login to view URL] I have configured this to use an AWS service, and attach it below with a test account details in a text file, plus required DLLs. The Unity project is also attached which is essentially the same as the above example project. However there is possibly a problem with threading which means the the final 'await' command is deadlocked or otherwise not returning a response. You'll see I tried experimenting with some Unity async helper libraries, however I have yet to overcome the problem and I am requesting help.