ADBannerView no internet connection error

Question

I've integrated iAd in my application. It works when I have an internet connection, but if I have no internet connection the ADBannerView repeats the same error message infinitely.

func addiAd()
{
    iAdBanner.frame = CGRectMake(0, 400 320 50
    iAdBanner.hidden = true
    iAdBanner.delegate = self
    self.view.addSubview(iAdBanner)
}

func bannerView(banner: ADBannerView!, didFailToReceiveAdWithError error: NSError!)
{
    println(error)
}

2015-06-21 04:43:04.857 Music Player[6219:121409] ADBannerView error: Unknown error
2015-06-21 04:43:04.866 Music Player[6219:121409] ADBannerView error: Unknown error
2015-06-21 04:43:04.876 Music Player[6219:121409] ADBannerView error: Unknown error
2015-06-21 04:43:04.885 Music Player[6219:121409] ADBannerView error: Unknown error
2015-06-21 04:43:04.895 Music Player[6219:121409] ADBannerView error: Unknown error
2015-06-21 04:43:04.906 Music Player[6219:121409] ADBannerView error: Unknown error
2015-06-21 04:43:04.918 Music Player[6219:121409] ADBannerView error: Unknown error