According to Google, “The root cause was an issue in our automated quota management system which reduced capacity for Google’s central identity management system, causing it to return errors globally. As a result, we couldn’t verify that user requests were authenticated and served errors to our users.”
This also impacted the ability to use websites or apps where the user is logged in using their Google credentials.
Joe Brown, an editor who has worked for Road and Track and Car and Driver, posted to Twitter that the outage was affecting the ability to turn the lights on in his child’s bedroom, as they are connected to Google Nest.
“The authentication system issue was resolved at 4:32AM PT,” Google said early Tuesday morning. “All services are now restored. We apologise to everyone affected, and we will conduct a thorough follow up review to ensure this problem cannot recur in the future.”
However, DownDetector, which calls itself a “Realtime overview of issues and outages with all kinds of services,” updated around 3PM Tuesday to show that GMail was once again down.
According to Google, “The affected users are able to access Gmail, but are seeing error messages, high latency, and/or other unexpected behavior.”
Protonmail, an end-to-end encrypted e-mail service, noted that every e-mail sent from a Protonmail.com address to a Google address was being immediately bounced back.
Monday saw almost 40,000 reports by individual users. On Tuesday, almost 1,800 users had reported outages.
Google’s main product, Search, was unaffected.