Can't generate APK after add admob plugin

Hi guys!

Yesterday I decided to add admob to my application because the number of users grows up and I need to pay money to make application database works fine for them

But after added admob plugin, I always get “BUILD FAILED” when i tried to generate the APK using this command line “ionic cordova build android --prod”.

So Is there any solution to fix this problem ?

I think I solved the problem by remove and downgrade the platform to 6.3.~