The GFE is an HTTP/TCP reverse proxy which is used to serve requests to many Google properties including: Search, Ads, G Suite (Gmail, Chat, Meet, Docs, Drive, etc.), Cloud External HTTP(S) Load Balancing, Proxy/SSL Load Balancing, and many Cloud APIs.

  ...

  Google engineers were alerted to the outage three minutes after impact began at 2020-09-24 18:03, and immediately began an investigation. At 18:15 the first service change, which significantly increased the number of programmed backends, was rolled back. At 18:18 the second service configuration change was rolled back. Google engineers started seeing recovery at 18:20 and at 18:33 the issue was fully mitigated.

A Google Front End (GFE) outage is a costly one, especially since it affected ads too. Oof.