google-maps-at-88-mph VS Flask Google Maps

I've recently written a tool, Google Maps at 88 mph (the name's a reference) that collects all available imagery versions for a given area in the form of a GIF. In the last week, I've extended it to handle the 45-degree imagery (looking at cities at an oblique angle) available via an API.

I am building my first ever flask app and I installed the flask-googlemaps extension which everything seems like it should be working.. API response is 200, no errors in console about api key, and only the following messages show (see image), which I don't think would be a problem, but please correct me if I am wrong as these are from the package itself so not too sure... But just wondering what I should be looking for to fix my app, as my screen loads empty.

No luck in Stack Overflow for the moment, so I'm posting this here as well :) I'm a newbie writing a Flask web app that displays in a Google Map a series of locations stored in a SQLite database. In order to do this I'm trying to use the Flask-GoogleMaps extension (https://github.com/flask-extensions/Flask-GoogleMaps), but even when I only try the example code given in the documentation the map won't display in the page. The server returns a 403 error: