Since July of 2016, Google API key is mandatory. The key is free, however you need to insert it on your site here:
Once you have entered the API key, your map should function properly.
Please make sure that the Browser API key is inserted in the Browser API field and the Server key in the Server API field.(see the highlighted part of the image)
- In case you are still having issues, make sure that your plug-in and Super Map add-on are up to date.