GADRequest request delegate does not always receive resposne - ios

Question

I am working on an iOS app that uses Google Ad SDK. The view controller that is supposed to display the ad is a delegate of GADBannerViewDelegate and GADSwipeableBannerViewDelegate.
The ad comes in just fine most of the time. Sometimes however, AdMob seems to hang and I don't get a response whatsoever in my delegate.
Is there something I have done wrong? Alternatively, is there a way to detect this behavior?
I initialize the ad banner and then in viewWillAppear I reload the ad (assuming it's not already loading). It usually works just fine but again, it sometimes doesn't.
Here is the relevant code:
UPDATE::
I changed the code but to no avail. Here is new code (got rid of previous two methods):
-(void)resetAdView:(UIViewController *)rootViewController {
[self.adMob_ActivityIndicator startAnimating];
if (adBanner_ == nil) {
adBanner_ = [[DFPSwipeableBannerView alloc]
initWithFrame:CGRectMake(30, 365, 300, 150)];
}
[adBanner_ setHidden:YES];
if (isLoaded_) {
GADRequest *request = [GADRequest request];
[adBanner_ loadRequest:request];
[self.scrollView addSubview:adBanner_];
} else {
adBanner_.delegate = self;
adBanner_.rootViewController = rootViewController;
adBanner_.adUnitID = AD_UNIT_ID;
GADRequest *request = [GADRequest request];
[adBanner_ loadRequest:request];
[self.scrollView addSubview:adBanner_];
}
}
My instance variables are :
DFPSwipeableBannerView *adBanner_;
BOOL isLoaded_;

Answer 1

This might be due to lack of ad inventory.
Did you implement the banner view's error catching delegate function?
(void)adView:(DFPBannerView *)view didFailToReceiveAdWithError:(GADRequestError *)error
If this delegate method isn't implemented in your code, implement it and log the error object to get a detailed error description.

Answer 2

I ended up just wiping the banner view from the superview and completely re-initializing it and the request. This doesn't solve the problem of the hanging response but now if you switch to a different view and come back to this one, the ad does reload. It's possible that I was simply adding too many views into my scrollview which will not be the case anymore.
-(void)resetAdView:(UIViewController *)rootViewController {
// in reset method
[self.adMob_ActivityIndicator startAnimating];
adBanner_ = nil;
for (UIView *subview in self.scrollView.subviews) {
if (subview.tag == 666) {
// removing banner view from superview
[subview removeFromSuperview];
}
}
// (re) initializing banner view
adBanner_ = [[DFPSwipeableBannerView alloc]
initWithFrame:CGRectMake(30, 365, 300, 150)];
[adBanner_ setHidden:YES];
// setting up and requesting ad
adBanner_.delegate = self;
adBanner_.rootViewController = rootViewController;
adBanner_.adUnitID = AD_UNIT_ID;
GADRequest *request = [GADRequest request];
[adBanner_ loadRequest:request];
adBanner_.tag = 666;
[self.scrollView addSubview:adBanner_];
}