Code=1011 “Display Format Mismatch” facebook
i was using same test id for the Facebook Banner and Interstitial ad unit
Seperating the Adunit ids worked for me like:
<string name="fb_placement_id" translatable="false">IMG_16_9_APP_INSTALL#732965463811239_733275773780208</string>
<string name="fb_placement_interstitial_id" translatable="false">IMG_16_9_APP_INSTALL#YOUR_PLACEMENT_ID</string>