angular: HTTP 503 in Chrome -- angular.io is currently unable to handle this request.

I’m submitting a…

[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report  
[ ] Performance issue
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question
[X] Other... Please describe: Frequent 503 when attempting to access angular.io docs over the last week

Current behavior

Randomly, angular.io docs will stop working from within Chrome. Reloading the page in Chrome, clearing cache, etc. does not resolve the issue. However, curl https://angular.io/ will produce valid HTML, suggesting an issue with how docs are served to browsers.

Minimal reproduction of the problem with instructions

Enter https://angular.io/ in the Chrome omnibar. See 503 server error. Clear cache, force reload (SHIFT-F5), still see 503.

Environment

Window 10

Browser:

• Chrome 69.0.3497.81 (Official Build) (64-bit) (cohort: 69_win_81) -> up to date, current stable/public version
• Chrome (Android) version XX
• Chrome (iOS) version XX
• Firefox version XX
• Safari (desktop) version XX
• Safari (iOS) version XX
• IE version XX
• Edge version XX