When I go to flask run and open the web server, the google maps background is darkened and says "For development purposes only" and when I try to use the search feature nothing changes. Also I can only zoom in to see streets and no further. Any ideas? Thanks
That is how things are since July 2018. Google added a paywall; you can register for an API KEY (requires credit card), or use it the way it is. Look in the browser console, and you'll see messages. This should not prevent your progress.
And make sure to have a look at the course home page on edX. The syllabus has changed for 2019; the mashup pset has been retired.