I'm sometimes getting "empty" ads in my app, that is, ads that show no
ad text or image, just the "Ads by AdMob" text and the logo on the
right, as can be seen in this screenshot:
https://sites.google.com/site/schulzeharmonics/emptyad.png
Those empty ads are also not clickable, so it's not just a problem of
black text on black background; they appear often, but the next
refresh may bring in a fully-functioning ad. And it's happening with
multiple publisher ids.
Is anybody seeing this, and more importantly, has anybody got a
solution?