Hi there,
Thanks for providing your Ad Unit ID to help in investigating your issue.
Upon testing your Ad Unit ID on our sample apps, I have successfully replicated your issue when I tried setting the size of the NativeExpressAdView outside the allowed size. Native Express Ads have an Ad Size convention which should be followed or ads will not be shown since the ad is trying to request and render an Ad Size not belonging to any template size. Could you please try resizing your NativeExpressAdView based on the template size you selected for your Native Express Ad and the Ad Size convention linked above.
If, however, you are complying with the Ad Size convention for Native Express Ads, kindly provide a sample code snippet on how you are implementing your Native Express Ads, or a sample project that can replicate the error.
Feel free to get back to us if you encounter any more issues.
Regards,
Joshua Lagonera
Mobile Ads SDK Team