Thank you for contacting us. Since you were able to display Ads when changing the bundle Id, then it's safe to assume that your code implementation of the Mobile Ads SDK is correct. If you are only not able to load ads when using a particular bundle Id, then this seems to be more of an Ad serving issue rather than anything specific to the Mobile Ads SDK. Please reach out to the
Product Support Team and share your Ad unit and bundle id with them or use
this troubleshooter for further assistance on this.