I have had this issue for days and can't seem to get what the problem is.
I have developed a 2D Unity game for Android and had been testing it with a Samsung Galaxy Note 3 (Android 4.4) and had absolutely no issues - however, when I tested it with a Galaxy S6 (Android 7.0), not even test ads show up. The ads are also working fine in emulators. I took a look at the logcat and I consistently get the 2 below errors.
1)E/Ads: Google Mobile Ads SDK initialization functionality unavailable for this session. Ad requests can be made at any time. 2)E/Ads: This app is using a lightweight version of the Google Mobile Ads SDK that requires the latest Google Play Services to be installed, but Google Play services are either missing or out of date.
To my knowledge, I am not using a Lite version of the SDK so for me, this doesn't make sense - did anyone else get around this somehow? I have seen many people having issues with Android 6.0 and up, but no consistent answers. Thank you so much for your time.
Download Latest JAR file from here. It will be a unity package. Just open it with your game project opened in Unity or follow this. Then resolve your dependencies.
If you don't know how to resolve follow,
In the Open Unity project, navigate to the Assets dropdown menu and choose Play services resolver > Android Resolve Select the Resolve or Force Resolve
Then wait for Resolve to be completed.
After that, you won't see the errors.
Hope Helpful!