I am trying to add Native Ads in my android app. But I am continually getting error Failed to load ad with error code 3. I have tried it with other test Ad units and in that case my code is working fine, ads are displaying. But when I am trying to show Banner Ads from same account, I am getting error code 0. I am not able to display any type of ad from my account.
Note:- I have created this account 3 days before and Billing is also enabled and verified in this.