Issues connecting DynamoDB from Orleans cluster

I am trying to connect to dynamoDB from the SiloHost. However, I end up getting the following error:

`System.Net.Http.HttpRequestException: No such host is known.
---> System.Net.Sockets.SocketException (11001): No such host is known.
at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
--- End of inner exception stack trace ---
at System.Net.Http.ConnectHelper.ConnectAsync(String host, Int32 port, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean allowHttp2, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean doRequestAuth, CancellationToken cancellationToken)
at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
at System.Net.Http.HttpClient.FinishSendAsyncUnbuffered(Task`1 sendTask, HttpRequestMessage request, CancellationTokenSource cts, Boolean disposeCts)
at Amazon.Runtime.HttpWebRequestMessage.GetResponseAsync(CancellationToken cancellationToken)
at Amazon.Runtime.Internal.HttpHandler`1.InvokeAsync[T](IExecutionContext executionContext)
at Amazon.Runtime.Internal.Unmarshaller.InvokeAsync[T](IExecutionContext executionContext)
at Amazon.Runtime.Internal.ErrorHandler.InvokeAsync[T](IExecutionContext executionContext)
at Amazon.Runtime.Internal.ErrorHandler.InvokeAsync[T](IExecutionContext executionContext)
at Amazon.Runtime.Internal.CallbackHandler.InvokeAsync[T](IExecutionContext executionContext)
at Amazon.Runtime.Internal.EndpointDiscoveryHandler.InvokeAsync[T](IExecutionContext executionContext)
at Amazon.Runtime.Internal.EndpointDiscoveryHandler.InvokeAsync[T](IExecutionContext executionContext)
at Amazon.Runtime.Internal.CredentialsRetriever.InvokeAsync[T](IExecutionContext executionContext)
at Amazon.Runtime.Internal.RetryHandler.InvokeAsync[T](IExecutionContext executionContext)
at Amazon.Runtime.Internal.RetryHandler.InvokeAsync[T](IExecutionContext executionContext)
at Amazon.Runtime.Internal.CallbackHandler.InvokeAsync[T](IExecutionContext executionContext)
at Amazon.Runtime.Internal.CallbackHandler.InvokeAsync[T](IExecutionContext executionContext)
at Amazon.Runtime.Internal.ErrorCallbackHandler.InvokeAsync[T](IExecutionContext executionContext)
at Amazon.Runtime.Internal.MetricsHandler.InvokeAsync[T](IExecutionContext executionContext)
at Orleans.Clustering.DynamoDB.DynamoDBStorage.GetTableDescription(String tableName)
at Orleans.Clustering.DynamoDB.DynamoDBStorage.InitializeTable(String tableName, List`1 keys, List`1 attributes, List`1 secondaryIndexes, String ttlAttributeName)
at Orleans.Clustering.DynamoDB.DynamoDBMembershipTable.InitializeMembershipTable(Boolean tryInitTableVersion)
at Orleans.Runtime.MembershipService.MembershipTableManager.Start()
at Orleans.Runtime.MembershipService.MembershipTableManager.<>c__DisplayClass54_0.<-Participate>g__OnRuntimeGrainServicesStart|0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at Orleans.Runtime.SiloLifecycleSubject.MonitoredObserver.OnStart(CancellationToken ct)
at Orleans.LifecycleSubject.OnStart(CancellationToken ct)
at Orleans.Runtime.Scheduler.AsyncClosureWorkItem.Execute()
at Orleans.Runtime.Silo.StartAsync(CancellationToken cancellationToken)
at Orleans.Hosting.SiloHost.StartAsync(CancellationToken cancellationToken)
at OrleansSnapperSiloHost.Program.RunMainAsync() in C:\Users\Administrator\Desktop\Snapper-Orleans\SnapperSiloHost\Program.cs:line 115`

This is a windows host on AWS. I have ensured that the firewall is off, all network connection is allowed.

` using (var file = new StreamReader(Constants.credentialFile))
{
ServiceRegion = file.ReadLine();
Console.WriteLine(ServiceRegion);
AccessKey = file.ReadLine();
Console.WriteLine(AccessKey);
SecretKey = file.ReadLine();
Console.WriteLine(SecretKey);
}

Action dynamoDBOptions = options =>
{
options.AccessKey = AccessKey;
options.SecretKey = SecretKey;
options.TableName = Constants.SiloMembershipTable;
options.Service = ServiceRegion;
options.WriteCapacityUnits = 10;
options.ReadCapacityUnits = 10;
};
Console.WriteLine("Using DynamoDB");
builder.UseDynamoDBClustering(dynamoDBOptions);`

This is how I am connecting.
Please help! Thanks!

Read Program.cs at line 115 and the UseDynamoDBClustering configuration, then trace the DynamoDBStorage.InitializeTable and GetTableDescription calls shown in the stack trace. Verify what ServiceRegion contains and whether the SiloHost can resolve the configured DynamoDB endpoint; done means the silo initializes its membership table without the reported HttpRequestException.

Written by the indexing model from the issue text.