I have integrated admob banner ads as per following steps of admob documentation.
I am getting test ads with emulator. And also getting ads using below instructions.
AdRequest.Builder.addTestDevice("F3F05FA129EF5A4FEEF9DCC4F3A96936")
If i run application using release build configuration getting error below error logs.
07-14 17:50:01.461 16693-16693/xx.xxxxx I/Ads: Starting ad request.
07-14 17:50:02.164 16693-16693/xx.xxxxx I/Ads: Use AdRequest.Builder.addTestDevice("F3F05FA129EF5A4FEEF9DCC4F3A96936") to get test ads on this device.
07-14 17:50:02.913 16693-16847/xx.xxxxx W/Ads: There was a problem getting an ad response. ErrorCode: 0
07-14 17:50:03.478 16693-16693/xx.xxxxx W/Ads: Failed to load ad: 0
And if export apk with release configuration getting below error.
07-14 18:00:19.125 23074-23074/xx.xxxxx I/Ads: Starting ad request.
07-14 18:00:19.126 23074-23074/xx.xxxxx I/Ads: Use AdRequest.Builder.addTestDevice("F3F05FA129EF5A4FEEF9DCC4F3A96936") to get test ads on this device.
07-14 18:00:19.656 29969-23211//xx.xxxxx W/Ads: Received error HTTP response code: 403
07-14 18:00:20.040 23074-23074/xx.xxxxx W/Ads: Failed to load ad: 0
Is there any issue with admob bita account ? (https://apps.admob.com/v2/home?pli=1)
Finally, I got my answer from google forum.
https://groups.google.com/d/msg/google-admob-ads-sdk/dQjjRAdaPrE/Sb-fXslHBwAJ
In my case, its something that Google AdMob has blocked my package name and after changing the package name its worked fine with me.