TL;DR – put the following line in your app-ads.txt file:

google.com, pub-3940256099942544, DIRECT, f08c47fec0942fa0

Long version: When I upgraded to iOS 15 and Xcode 13, I went to upgrade all my apps. I test them all with Admob test ads, the way you should. When I got done with the changes I made, started getting the error:

Google> Cannot find an ad network adapter with the name(s): (
"com.google.DummyAdapter"
). Remember to link all required ad network adapters and SDKs, and   set -ObjC in the 'Other Linker Flags' setting of your build target.

Which isn’t very helpful. At first I thought there was a bug in a Pod dependency, or one of the libraries. I downloaded an example app from Admob, and that worked. So I thought there was a bug in my code. I looked for “-ObjC” in the ‘Other Linker Flags’ – yup, it was there. I looked all over the web for a solution to this, only to find there were many other people with the same issue.

The guidance from Admob on their forums? That error occurs when there are no ads available (or if the -ObjC isn’t there in the linker flags). So….how do they NOT have test ads? I mean, that’s something that’s always available, right?

Since I do this in my spare time, I let this slide for months. Yesterday, I looked into it again, and spent several hours looking around to see what might be the case. Eventually, I searched for “Admob not showing test ads”, and ran across a thread on Reddit in the r/admob forum. Down at the bottom, user ahmedbilal12321 had the same problem, and solved it by adding the line:

google.com, pub-3940256099942544, DIRECT, f08c47fec0942fa0

to the app-ads.txt. This is specifically added so your apps can show test ads.

This is something I didn’t do when I started using app-ads.txt earlier in the year, and test ads showed up for me. Sure enough, this is also in the Admob documentation for test ads – I bypassed that in the documentation when I was searching for a solution.

I added that line to app-ads.txt, waited until Google scanned the file, tried it out, and….. it didn’t work. It was pretty late last night at this point, and I figured that after Google scanned the file, it was going to take some time for it to filter through the rest of the system.

I tried it a few minutes before I wrote this post, and it worked.

That thread was the only place I’ve seen this mentioned. I wanted to post something in hopes it will help someone else. Thanks to ahmedbilal12321 for posting that!

Several other users (specifically on Stack Overflow) have posted they ran into this problem, and ran REAL Admob ads in their apps to test to see if it’s working. DO NOT DO THIS. It will get you suspended or even banned. Add the test identifier for the simulator and any devices you might test on as admob suggests AND run using the test banner/interstitial/whatever ads they provide as tests. DO BOTH. If you do one, and not the other, it can also get your suspended or banned.