An error occurred while saving the commentBogdan commented
Same issue. Where to add Google API? I found just where to add Snazzy Maps API but did not solve the problem
Later edit: although I use snazzy maps, in the wordpress theme options I found the google map API field. I added there the Google API and it works. In my case, in the theme options, I had a contact field where I could define the contact page, add location, GPS target, phone number, Google API and so on.