ios - Shared iAd banner unloads ad after dismissing navigation popover -

i saw few other similar questions find answers... have shared iad banner. problem when load in modally presented navigationcontroller tableviewcontroller, when dismiss tableviewcontroller ad banner in mainviewcontroller loses ad , receive following error:

adbannerview: unhandled error (no delegate or delegate not implement didfailtoreceiveadwitherror:): error domain=aderrordomain code=7 "the operation couldn’t completed. ad unloaded banner" userinfo=0x5b60e283649 {adinternalerrorcode=7, nslocalizedfailurereason=ad unloaded banner, adinternalerrordomain=aderrordomain}

the view setup this: mainviewcontroller --> navigationcontroller --> tableviewcontroller

at point in app modally present viewcontroller shared ad , don't experience issue. (mainviewcontroller --> viewcontroller)

here code tableviewcontroller:

.h

#import <uikit/uikit.h> #import <iad/iad.h> #import "appdelegate.h"  @interface tableviewcontroller : uitableviewcontroller <adbannerviewdelegate>  @property (strong, nonatomic) iboutlet uitableview *table; @property (strong, nonatomic) adbannerview *adview;  @end 

.m

-(void) viewwillappear:(bool)animated {     [super viewwillappear:yes];     // insert ad bar     appdelegate *appdelegate = (appdelegate *)[[uiapplication sharedapplication ]delegate];     _adview = [appdelegate adview];     _adview.delegate = self;     self.candisplaybannerads = true;      if (ipad) {         [_adview setframe:cgrectmake(0, self.view.frame.size.height - 65, 320, 65)];     }     else {         [_adview setframe:cgrectmake(0, self.view.frame.size.height - 50, 320, 50)];     }     if (!_adview.bannerloaded) {         [_adview setalpha:0];     }     [self.view addsubview:_adview]; }  - (void)bannerviewdidloadad:(adbannerview *)banner {     [uiview beginanimations:nil context:null];     [uiview setanimationduration:1];     [banner setalpha:1];     [uiview commitanimations]; }  - (void)bannerview:(adbannerview *)banner didfailtoreceiveadwitherror:(nserror *)error {     [uiview beginanimations:nil context:null];     [uiview setanimationduration:1];     [banner setalpha:0];     [uiview commitanimations]; } 

any tips appreciated. thanks

the problem because using:

self.candisplaybannerads = true; 

as as:

if (ipad) {     [_adview setframe:cgrectmake(0, self.view.frame.size.height - 65, 320, 65)]; } else {     [_adview setframe:cgrectmake(0, self.view.frame.size.height - 50, 320, 50)]; } if (!_adview.bannerloaded) {     [_adview setalpha:0]; } [self.view addsubview:_adview]; 

and created 2 instances of ad bar.