react-native-admob ERROR_CODE_INTERNAL_ERROR

I'm trying to use react-native-admob. It shows ad time to time. Most of the time it gives a error ERROR_CODE_NETWORK_ERROR in chrome debugging. When I do logging through native debugging, the RNAdMobInterstitialAdModule fires with error 0.

<AdMobBanner
     bannerSize='smartBannerPortrait'
     adUnitID='ca-app-pub-3940256099XXXXXX/XXXXXXXXXX'
     testDeviceID='EMULATOR'
     didFailToReceiveAdWithError={ (error) => console.log(error) }
/>

Any ideas what to do next to solve this problem?