I was chatting with @lamagalhaes about this on Intercom, so I will share the resolution here.
For a Google Maps API key, it’s not enough to have an unrestricted key.
You need the Maps SDK for Android and/or the Maps SDK for iOS enabled, depending on what platforms you plan to download/publish your app for.
To see if these SDKs are enabled in your Google Cloud project, simply go to the Google Cloud Platform and search for ‘maps’:
And click on the SDK(s) you want to see if they are enabled. See the green tick and the ‘API Enabled’ text here:
If the SDKs are not enabled, simply enable them, and your app should work as expected!
If the SDKs are enabled, and you still don’t see the map in your app, please reach out and we will find out the cause of this behavior.