Graeme Hill's Dev Blog

Singleton WCF service gotcha: allowing more than 10 connections

Star date: 2010.091

By default, an instance of a WCF service can only have 10 connections at a time. If your service is a singleton then there is obviously only one instance, which means that only 10 clients can connect to your service at a time. All subsequent connection attempts will result in timeouts if one of the 10 spots is not freed up. You can easily change this from the default by adding a serviceThrottling entry to your behavior definition in the app.config/web.config file. Here's an example that cranks the max up to 50:

    maxConcurrentInstances="50" />