Your error occurs because you do not have a Password api
If you look at the script you use, there is something called
key = AIzaSyBu-916DdpKAjTmJNIgngS6HL_kDIKU0aU & callback
this is a key of api that you will have to get with Google
Once you get your api key, you only substitute in that part of key = ....
I leave a link with the complete steps here
Steps to Obtain an API Key
In this section, we explain how to authenticate your app in the Google Maps JavaScript API with your own API key.
Follow these steps to obtain an API key:
Go to the Google API Console.
Create or select a project.
Click Continue to enable the API and any related services.
On the Credentials page, get an API key (and configure its restrictions).
Note: If you already have an API key without restrictions or a key with browser restrictions, you can use it.
To avoid quota theft, protect your API key by following these best practices.
(Optional) Enables billing. For more information, see the usage limits section.
Copy all the code of the instructions on this page to your text editor. If you do not have a text editor, we recommend using Notepad ++ (for Windows); TextEdit (for macOS); and gedit, KWrite and others (for Linux machines).
Replace the key parameter value of the URL with your own API key (the one you just got).
Save this file with a name that ends in .html, such as google-maps.html.
Load the HTML file to a web browser: drag it from your desktop to the browser. In most operating systems, another alternative is to double-click on the file.