Not able to trigger main error handler in my node express application

I am using node express (4.15.2), with the default express generator function to handle errors.

The code is:

   // error handler
   app.use(function(err, req, res, next) {
      // this function is never called
      // set locals, only providing error in development
      res.locals.message = err.message;
      res.locals.error = req.app.get('env') === 'development' ? err : {};
      // render the error page
      res.status(err.status || 500);
      res.render('error');
    });

In my application I using the following line of code when I need to create an error:

new Error('Some custom error');

But the error handler is never called.

Notes: the error handler is placed after the latest app.use but before app.listen.

Any ideas what could cause this issue and how to fix it?

via GibboK