An outage at Google is causing Google’s older script loader at https://www.google.com/jsapi to display and error and thus the library to not be sent to the browser. When this happens, you will see an error in the Developer Tools console that states “Failed to load resource: the server responded with a status of 502 jsapi:1″” Google is currently working on resolving the error and is working on a fix for the problem. The good news is that you can easily switch to their new library loader.”
Source: https://www.bleepingcomputer.com/news/google/google-outage-causing-google-charts-and-other-apis-to-not-work/