Endpoint Security and XPC

Hi.

I'm trying to connect to my ES System Extension from it's App using XPC.

The App code:

Code Block 
_connection = [[NSXPCConnection alloc] initWithMachServiceName:@“TeamID.ExtensionBundleId.xpc” options:NSXPCConnectionPrivileged];
  [_connection resume];

The Extension code:

Code Block 
_connectionListener = [[NSXPCListener alloc] initWithMachServiceName:@“TeamID.ExtensionBundleId.xpc”];
  _connectionListener.delegate = self;
  [_connectionListener resume];

where TeamID and ExtensionBundleId are substituted with real values.

The listener's delegate in Extension conforms to NSXPCListenerDelegate.

Problem: the Extension's callback

Code Block 
- (BOOL)listener:(NSXPCListener *)listener shouldAcceptNewConnection:(NSXPCConnection *)newConnection

is never executed.

Also tried with setting NSEndpointSecurityMachServiceName in Extension's plist to custom name, without success.

What am I doing wrong?
Thanks.