Invalid password should raise AuthenticationFailedException instead it raises ServiceNotAvailableException

static async Task Main(string[] args)

 {

    try

     {

          var cluster = await Couchbase.Cluster.ConnectAsync("couchbase://localhost",          "Administrator", "password");

var queryResult = await cluster.QueryAsync<dynamic>("select * from `travel-   sample`.inventory.airport limit 2");

    await foreach (var row in queryResult)

   {

    Console.WriteLine(row);

    }

 }

 catch (CouchbaseException ex)

 {

 Console.WriteLine(ex); 

 }

 catch (Exception ex)

 {

 Console.WriteLine(ex);

 }

Console.Read();

 }

Couchbase.ServiceNotAvailableException: Service n1ql not available.

 at Couchbase.Core.ClusterContext.GetRandomNodeForService(ServiceType service, String bucketName)

 at Couchbase.Core.ServiceUriProvider.GetRandomQueryUri()

 at Couchbase.Query.QueryClient.ExecuteQuery[T](QueryOptions options, ITypeSerializer serializer, IRequestSpan span)

 at Couchbase.Query.QueryClient.QueryAsync[T](String statement, QueryOptions options)

 at Couchbase.Cluster.<>c__DisplayClass33_0`1.<<QueryAsync>g__Func|0>d.MoveNext()

--- End of stack trace from previous location where exception was thrown ---

 at Couchbase.Core.Retry.RetryOrchestrator.RetryAsync[T](Func`1 send, IRequest request)

 at Couchbase.Cluster.QueryAsync[T](String statement, QueryOptions options)

 at ScopeLevelQuery.Program.Main(String[] args) in /Users/arun.vijayraghavan/ScopeLevelQuery/ScopeLevelQuery/Program.cs:line 24