I implemented a Admob banner ad in my app while in development and it worked perfectly as I tested it with Googles test id and I tested it with my own id which worked but once I published it on the App Store devices that downloaded my app do not display the ad. My personal phone which I set as a test device on Admobs website displays the ad. Since I published the app about 3 days ago I I have recieved 100 Admob network requests which doesn't make sense as an ad is not displayed. I have researched everywhere and haven't found a solution as of yet.
It eventually displayed ads once I was able to link my app to the Admob website, so I guess it was just a waiting game.