Hi,
Error code 3, no fill error means that the ad request was successful, but no ad was returned due to lack of ad inventory. Kindly note that the SDK just requests ads to the ad server and does not have any control on the ads it serves.
This is more of an Ad serving concern rather than anything specific to the code implementation of the Mobile Ads SDK. I would recommend that you refer to AdMob Error Codes & Logs for more details about the issue.
Kindly provide the below information via the reply to author option for further investigation
Mobile Ads SDK Team |