接入谷歌admob广告报错,whose view is not in the window hierarchy!

[1667973708 (nahsey)]

cocos creator打包的ios项目，接入谷歌的admob激励视频的时候，报如下的错误：
< GADFullScreenAdViewController: 0x16d2d1d0 > on < GADViewController: 0x16e6d070 > whose view is not in the window hierarchy!