Workaround for lost NotificationHub ConnectionString. The NotificationHub ConnectionString can get lost after the app has been running for a while. We will be updating the service shortly but in the mean time here is a workaround that fixes the issue.

WebApiConfig.cs

    public static class WebApiConfig
    {
        public static void Register()
        {
            ConfigOptions options = new ConfigOptions();
            HttpConfiguration config = ServiceConfig.Initialize(new ConfigBuilder(options));

            // Workaround for notification hub connection string going missing.
            IServiceSettingsProvider settingsProvider = config.DependencyResolver.GetServiceSettingsProvider();
            ServiceSettingsDictionary settings = settingsProvider.GetServiceSettings();
            string notificationHubConnectionString;
            if (settings.TryGetValue("MS_NotificationHubConnectionString", out notificationHubConnectionString))
            {
                ConnectionSettings notificationHubSettings =
                    new ConnectionSettings(ServiceSettingsKeys.NotificationHubConnectionString, notificationHubConnectionString);
                settings.Connections.Add(ServiceSettingsKeys.NotificationHubConnectionString, notificationHubSettings);
            }
        }
    }