log4js with fileappender in express app errorhandler doesn't work

Problem

I have a node.js express app with log4js configured. Running the app in browser (this works normally) calls error middleware because i do a next(err) inside the matching router.

What happend

After calling the apps url the console.log(logger) function outputs the object logger to console - logger object is valid - and after that Log 2 test appears also. But when is look into the server.log file i can see only one line of logging:

[2014-08-22 13:15:06.343] [INFO] default - Log 1 test

The second line is missing.

Code

var log4js = require("log4js");


log4js.configure({
    appenders: [
        {
            type: 'file',
            filename: "./server.log",
            category:"default"
        },
        {
            type: 'console'
    }
  ]
});
var logger = log4js.getLogger("default");
logger.setLevel("DEBUG");
logger.info("Log 1 test");

app = express();
app.use(... some routers)

app.use(function (err, req, res, next) {
    console.log(logger);
    res.status(500).json({
        status: err.status,
        message: err.message
    });


    logger.info("Log 2 test"); // seems not to work

});

Any ideas?