Hello There,
Thanks for writing in!
Source Maps is not related in anyway with Google Maps. You can ignore the source maps error as it is not necessary in loading the page. It will only be used when you are debugging the page. https://www.html5rocks.com/en/tutorials/developertools/sourcemaps/
What is the google map embed code that you added? Please make sure that you added the correct embedded code and that the iframe is properly closed just like this for example:
<iframe src="https://www.google.com/maps/embed?pb=!1m18!1m12!1m3!1d3001350.6274039093!2d-78.0124850364091!3d42.724753743853924!2m3!1f0!2f0!3f0!3m2!1i1024!2i768!4f13.1!3m3!1m2!1s0x4ccc4bf0f123a5a9%3A0xddcfc6c1de189567!2sNew+York%2C+USA!5e0!3m2!1sen!2sph!4v1536292347818" width="600" height="450" frameborder="0" style="border:0" allowfullscreen></iframe>
Hope this helps.