Ad Banner not disappears. Scene refresh problem?

I have a main scene with an ad banner. The scene contains a button and when you press it a configuration popup appears. The popup appears modally on the main scene and when I close it I want the banner of the main scene to disappear. I have accessed the banner and used the admobObject.bannerView.Hide () method; but it does not disappears. If I change the scene and come back it disappears so I think I have to force the refresh of the main scene but I have not found any way to do it. Any clue about what is happening and how to solve it? Thanks.