If you see a "For development purposes only" text over your map and it's not loading correctly, it means there's an issue with your Google Maps API key.
Most of the time it's related to the Google Cloud Billing not enabled.
Solution
Go to your Google Cloud Billing settings and make sure you have billing enabled. You may need to select your current project at the top left.
Google requires your account to have billing enabled if your Google Cloud free trial has ended or if you've gone beyond its free monthly tier.
If you need more information on how to set up your Google Maps correctly, take a look at this guide: How to add a Google Maps API key to your store locator. π