Azure DocumentDB client calls result in an error from Azure WebJob

Question

I have a Continuous Azure Webjob that checks DocumentDb on each message from QueueTrigger. Use DocumentDB SDK 1.10 for .NET. I keep getting errors like this from time to time:

Only one usage of each socket address (protocol/network address/port) is normally permitted :443 at Microsoft.Azure.Documents.Client.GatewayServiceConfigurationReader.d__0.MoveNext()

I have dependency injection (StructureMap) through the JobActivator and use non-static method to process queue triggers within Functions class. use

DocumentClient is wrapped in a static class so it should be one instance per WebJob.

Also some web apps (ASP.NET MVC) use their own document db connection with same connection string from time to time. I could not find any information about this issue. What could be go wrong here?

Changed internal code:

class Program
{
    public static IReliableReadWriteDocumentClient Client { get; set; }
    static void Main()
    {
        Client = // initialize client with settings from app config
    }
}

public class Functions
{
    public async Task ProcessQueueMessage([QueueTrigger("myqueuename")] CustomerRequest customerRequest,
            TextWriter dashboardLogger)
    {
        // usage from some place which runs on QueueTrigger

        var customerRepository = new DocumentDbRepository<Customer>(Program.Client, databaseId,
                    () => "Customers");
       // additional logic
    }
}

Repository class is taken from here: https://github.com/Crokus/documentdb-repo