Handle AdMob adverts for Cordova on iOS and Android.
After several attempts and a pain in the head, I found where the problem was.
After exporting the game from Construct 3 and opening the "config.xml" file, I found that the "construct-mobile-advert" version was 1.7.2, and on npmjs.com the latest version is 1.7.3. So I changed it to "construct-mobile-advert" spec = "1.7.3" and everything worked fine.