Hi There,
I am another staff checking on the thread. I did taken sometime checking the root of the issue. It turns out that your 3rd party plugin, Ultimate Addons needs Google API key. So I disabled the custom code given by Paul. I took the api from your child theme’s functions.php file and supplied it to the Ultimate Addons > Google Maps. The error is now gone.
If you need anything else we can help you with, don’t hesitate to open another thread.