Question : event IPC remoting proxy channel sink

When my event fires, the following exception occurs:
This remoting proxy has no channel sink which means either the server has no registered server channels that are listening, or this application has no suitable client channel to talk to the server.

Client
const string mediatorUrl = "ipc://MediatorChannel/MediatorManager";
IDictionary prop = new Hashtable();
prop["portName"] = "MediatorChannel";
prop["authorizedGroup"] = "Everyone";

BinaryClientFormatterSinkProvider clientProvider = new BinaryClientFormatterSinkProvider(prop, null);
_channel = new IpcClientChannel(prop, clientProvider);

ChannelServices.RegisterChannel(_channel, false);
_serviceManager = (MediatorManager)Activator.GetObject(typeof(MediatorManager), mediatorUrl);

_serviceManager.OrderProcessingStarted += new EventHandler(ProcessingStarted);
_serviceManager.OrderProcessingCompleted += new EventHandler(ProcessingCompleted);

Server
IDictionary prop = new Hashtable();
prop["portName"] = "MediatorChannel";
prop["authorizedGroup"] = "Everyone";

BinaryServerFormatterSinkProvider serverProvider = new BinaryServerFormatterSinkProvider(prop, null);
serverProvider.TypeFilterLevel = TypeFilterLevel.Full;

_channel = new IpcServerChannel(prop, serverProvider);
 ChannelServices.RegisterChannel(_channel, false);

RemotingConfiguration.RegisterWellKnownServiceType(
    typeof(MediatorManager),
    "MediatorManager",
    WellKnownObjectMode.Singleton);

Answer : event IPC remoting proxy channel sink

Singletom just means that there will be just one instance of the server handling multiple requests unlike single call. why do you think the proxy creates a singleton. Did you means that for every proxy call a new singleton gets created at the server?