Hi there,
Ya, Google has made A LOT of changes to their API and API requirements recently. We’re working on an update to the plugin which we’ll roll out as soon as we can. But we find generally that users are still able to use the current version.
That to me suggests you most likely have a plugin conflict.
Please disable all other plugins except Maps Builder. If it works as expected at that point, re-activate each plugin one by one and check the functionality again until you experience the problem again. Then let us know which plugin caused the conflict and we’ll work on a workaround.
If after deactivating all plugins it still doesn’t work as expected it’s most likely then your theme. Switch to Twenty Sixteen and it should work fine (you won’t loose your theme settings and can safely switch back to your theme and all will be well again). If it works as expected after switching to Twenty Sixteen, point me to the theme you are using and I’ll see what I can come up with.
Thanks!