Mapify360 API Key Invalid

This is usually a sign that no all APIs we're enabled inside the Google Cloud Platform. 

Please see from video tutorials and PDF guide that there are two APIs you must enable. (Google Maps Javascript API and Places API)

If you're also using CitationOptimizer, you will also need to enable the 3rd API (CustomSearch)

Go to Settings page > API Key > and follow the video tutorials there or the PDF guide.

Have you also enabled billing on Google? Although they provide free credits, this must be done in order to work. 

Also, when you copy and paste the API key to paste it inside Mapify360, make sure that there are no empty spaces before or after.