As of the 22nd of June 2016, Google maps will now require all new maps to provide a Google maps API key.
An API Key is made up of a rather long string of alpha numerical characters.
If you see an error such as the one below then please double check you have entered in the correct API key as it likely that the API key entered is possibly incorrect.
If you are certain that the API key has been entered in correctly then you may want to log into your Google account and check that your API key is still valid.
If for any reason it is no longer valid or has been deleted then you will need to generate another key and update your Styled Map with the new API key.
Good news is your maps should continue to work as normal.
That said, if you do update to the latest version you may need to take some extra steps when you add or edit a map for the first time since updating.
The implementation of the user defined API key is known to (in some cases) possibly cause a conflict with the address autocomplete on existing maps.
In this instance you may see your location input has been greyed out and you are unable to save as it requires a valid location.
If this occurs you will need to delete the existing Styled Maps block from the page and then create a new version of it in its place.
Be sure to refresh your page or even clear the cache
(dashboard > System & Settings > Optimization > Clear Cache)
after deleting the block and before dragging a new instance of the Styled maps add-on onto the page.
After doing so if your location input is not showing an autocomplete dropdown menu as you type then please close the form and refresh your browser (F5) a few times then open the Styled Maps block again.
You should now be able to see the location autocomplete dropdown as you type.